diff --git a/src/kernel/curse.c b/src/kernel/curse.c
index 01e77eace..4a3e1c045 100644
--- a/src/kernel/curse.c
+++ b/src/kernel/curse.c
@@ -493,7 +493,7 @@ const curse_type * ct)
 /* ------------------------------------------------------------- */
 /* gibt bei Personenbeschränkten Verzauberungen die Anzahl der
  * betroffenen Personen zurück. Ansonsten wird 0 zurückgegeben. */
-int get_cursedmen(unit * u, const curse * c)
+int get_cursedmen(const unit * u, const curse * c)
 {
     int cursedmen = u->number;
 
@@ -631,7 +631,7 @@ curse *create_curse(unit * magician, attrib ** ap, const curse_type * ct,
 /* hier müssen alle c-typen, die auf Einheiten gezaubert werden können,
  * berücksichtigt werden */
 
-static void do_transfer_curse(curse * c, unit * u, unit * u2, int n)
+static void do_transfer_curse(curse * c, const unit * u, unit * u2, int n)
 {
     int cursedmen = 0;
     int men = get_cursedmen(u, c);
@@ -678,7 +678,7 @@ static void do_transfer_curse(curse * c, unit * u, unit * u2, int n)
     }
 }
 
-void transfer_curse(unit * u, unit * u2, int n)
+void transfer_curse(const unit * u, unit * u2, int n)
 {
     attrib *a;
 
diff --git a/src/kernel/curse.h b/src/kernel/curse.h
index 543755c2b..a4fd1c430 100644
--- a/src/kernel/curse.h
+++ b/src/kernel/curse.h
@@ -267,7 +267,7 @@ extern "C" {
 
     /* gibt bei Personenbeschränkten Verzauberungen die Anzahl der
      * betroffenen Personen zurück. Ansonsten wird 0 zurückgegeben. */
-    int get_cursedmen(struct unit *u, const struct curse *c);
+    int get_cursedmen(const struct unit *u, const struct curse *c);
 
     /* setzt/loescht Spezialflag einer Verzauberung (zB 'dauert ewig') */
     void c_setflag(curse * c, unsigned int flag);
@@ -277,7 +277,7 @@ extern "C" {
      * korrekt gehandhabt werden. Je nach internen Flag kann dies
      * unterschiedlich gewünscht sein
      * */
-    void transfer_curse(struct unit *u, struct unit *u2, int n);
+    void transfer_curse(const struct unit *u, struct unit *u2, int n);
 
     /* gibt pointer auf die erste curse-struct zurück, deren Typ ctype ist,
      * oder einen NULL-pointer
diff --git a/src/kernel/messages.c b/src/kernel/messages.c
index d3cd4f99b..b8d33f08c 100644
--- a/src/kernel/messages.c
+++ b/src/kernel/messages.c
@@ -258,15 +258,14 @@ message * msg_error(const unit * u, struct order *ord, int mno) {
     return msg_feedback(u, ord, msgname, "");
 }
 
-message * cmistake(const unit * u, struct order *ord, int mno, int mtype)
+void cmistake(const unit * u, struct order *ord, int mno, int mtype)
 {
-    message * result;
+    message * msg;
     UNUSED_ARG(mtype);
-    result = msg_error(u, ord, mno);
-    if (result) {
-        ADDMSG(&u->faction->msgs, result);
+    msg = msg_error(u, ord, mno);
+    if (msg) {
+        ADDMSG(&u->faction->msgs, msg);
     }
-    return result;
 }
 
 void syntax_error(const struct unit *u, struct order *ord)
diff --git a/src/kernel/messages.h b/src/kernel/messages.h
index a42342153..4eca65fc1 100644
--- a/src/kernel/messages.h
+++ b/src/kernel/messages.h
@@ -60,7 +60,7 @@ extern "C" {
 #define ADDMSG(msgs, mcreate) { message * mx = mcreate; if (mx) { assert(mx->refcount>=1); add_message(msgs, mx); msg_release(mx); } }
 
     void syntax_error(const struct unit *u, struct order *ord);
-    struct message * cmistake(const struct unit *u, struct order *ord, int mno, int mtype);
+    void cmistake(const struct unit *u, struct order *ord, int mno, int mtype);
     struct message * msg_error(const struct unit * u, struct order *ord, int mno);
 #ifdef __cplusplus
 }
diff --git a/src/kernel/unit.c b/src/kernel/unit.c
index 7b6f135fc..bdd5ac232 100644
--- a/src/kernel/unit.c
+++ b/src/kernel/unit.c
@@ -981,10 +981,9 @@ void move_unit(unit * u, region * r, unit ** ulist)
 /* ist mist, aber wegen nicht skalierender attribute notwendig: */
 #include "alchemy.h"
 
-void clone_men(unit * u, unit * dst, int n)
+void clone_men(const unit * u, unit * dst, int n)
 {
     const attrib *a;
-    int hp = u->hp;
     region *r = u->region;
 
     if (n == 0)
@@ -1073,11 +1072,9 @@ void clone_men(unit * u, unit * dst, int n)
         if (u->attribs) {
             transfer_curse(u, dst, n);
         }
-    }
-    if (dst) {
         set_number(dst, dst->number + n);
-        hp -= u->hp;
-        dst->hp += hp;
+        dst->hp += u->hp * dst->number / u->number;
+        assert(dst->hp >= dst->number);
         /* TODO: Das ist schnarchlahm! und gehoert nicht hierhin */
         a = a_find(dst->attribs, &at_effect);
         while (a && a->type == &at_effect) {
@@ -1530,7 +1527,9 @@ unit *create_unit(region * r, faction * f, int number, const struct race *urace,
 
     /* u->race muss bereits gesetzt sein, wird fuer default-hp gebraucht */
     /* u->region auch */
-    u->hp = unit_max_hp(u) * number;
+    if (number > 0) {
+        u->hp = unit_max_hp(u) * number;
+    }
 
     if (dname) {
         u->_name = strdup(dname);
diff --git a/src/kernel/unit.h b/src/kernel/unit.h
index beea74ee7..dede956b5 100644
--- a/src/kernel/unit.h
+++ b/src/kernel/unit.h
@@ -166,7 +166,7 @@ extern "C" {
     void set_level(struct unit *u, skill_t id, int level);
     int get_level(const struct unit *u, skill_t id);
     void transfermen(struct unit *src, struct unit *dst, int n);
-    void clone_men(struct unit *src, struct unit *dst, int n); /* like transfer, but do not subtract from src */
+    void clone_men(const struct unit *src, struct unit *dst, int n); /* like transfer, but do not subtract from src */
 
     int eff_skill(const struct unit *u, const struct skill *sv, const struct region *r);
     int effskill_study(const struct unit *u, skill_t sk, const struct region *r);
diff --git a/src/kernel/unit.test.c b/src/kernel/unit.test.c
index 54b07b63f..6ab8ee21a 100644
--- a/src/kernel/unit.test.c
+++ b/src/kernel/unit.test.c
@@ -525,6 +525,29 @@ static void test_unlimited_units(CuTest *tc) {
     test_cleanup();
 }
 
+static void test_clone_men(CuTest *tc) {
+    unit *u1, *u2;
+    region *r;
+    faction *f;
+    test_setup();
+    r = test_create_region(0, 0, NULL);
+    f = test_create_faction(NULL);
+    u1 = test_create_unit(f, r);
+    scale_number(u1, 10);
+    u2 = test_create_unit(f, r);
+    scale_number(u2, 0);
+    CuAssertIntEquals(tc, 10, u1->number);
+    CuAssertIntEquals(tc, 200, u1->hp);
+    CuAssertIntEquals(tc, 0, u2->number);
+    CuAssertIntEquals(tc, 0, u2->hp);
+    clone_men(u1, u2, 1);
+    CuAssertIntEquals(tc, 10, u1->number);
+    CuAssertIntEquals(tc, 200, u1->hp);
+    CuAssertIntEquals(tc, 1, u2->number);
+    CuAssertIntEquals(tc, 20, u2->hp);
+    test_cleanup();
+}
+
 CuSuite *get_unit_suite(void)
 {
     CuSuite *suite = CuSuiteNew();
@@ -533,6 +556,7 @@ CuSuite *get_unit_suite(void)
     SUITE_ADD_TEST(suite, test_unit_name);
     SUITE_ADD_TEST(suite, test_unit_name_from_race);
     SUITE_ADD_TEST(suite, test_update_monster_name);
+    SUITE_ADD_TEST(suite, test_clone_men);
     SUITE_ADD_TEST(suite, test_remove_unit);
     SUITE_ADD_TEST(suite, test_remove_empty_units);
     SUITE_ADD_TEST(suite, test_remove_units_without_faction);
diff --git a/src/reports.c b/src/reports.c
index 8287e41f7..1a269caa5 100644
--- a/src/reports.c
+++ b/src/reports.c
@@ -161,15 +161,15 @@ size_t report_status(const unit * u, const struct locale *lang, char *fsbuf, siz
         const char *lname = locale_name(lang);
         struct locale *wloc = get_locale(lname);
         log_warning("no translation for combat status %s in %s", combatstatus[u->status], lname);
-        locale_setstring(wloc, combatstatus[u->status], combatstatus[u->status]+7);
-        len = strlcpy(fsbuf, combatstatus[u->status]+7, buflen);
+        locale_setstring(wloc, combatstatus[u->status], combatstatus[u->status] + 7);
+        len = strlcpy(fsbuf, combatstatus[u->status] + 7, buflen);
     }
     else {
         len = strlcpy(fsbuf, status, buflen);
     }
     if (fval(u, UFL_NOAID)) {
-        len += strlcat(fsbuf+len, ", ", buflen-len);
-        len += strlcat(fsbuf+len, LOC(lang, "status_noaid"), buflen-len);
+        len += strlcat(fsbuf + len, ", ", buflen - len);
+        len += strlcat(fsbuf + len, LOC(lang, "status_noaid"), buflen - len);
     }
 
     return len;
@@ -201,7 +201,7 @@ const char *hp_status(const unit * u)
 
 void
 report_item(const unit * owner, const item * i, const faction * viewer,
-const char **name, const char **basename, int *number, bool singular)
+    const char **name, const char **basename, int *number, bool singular)
 {
     const resource_type *rsilver = get_resourcetype(R_SILVER);
 
@@ -251,7 +251,7 @@ const char **name, const char **basename, int *number, bool singular)
         if (name)
             *name =
             LOC(viewer->locale, resourcename(i->type->rtype,
-            NMF_APPEARANCE | ((i->number != 1 && !singular) ? GR_PLURAL : 0)));
+                NMF_APPEARANCE | ((i->number != 1 && !singular) ? GR_PLURAL : 0)));
         if (basename)
             *basename = resourcename(i->type->rtype, NMF_APPEARANCE);
         if (number) {
@@ -286,7 +286,7 @@ static size_t buforder(char *buffer, size_t size, const order * ord, int mode)
         WARN_STATIC_BUFFER();
     }
 
-    return bufp-buffer;
+    return bufp - buffer;
 }
 
 /** create a report of a list of items to a non-owner.
@@ -349,7 +349,7 @@ report_items(const unit *u, item * result, int size, const unit * owner,
     return n;
 }
 
-static void report_resource(resource_report * result, const resource_type *rtype, 
+static void report_resource(resource_report * result, const resource_type *rtype,
     int number, int level)
 {
     assert(rtype);
@@ -381,7 +381,7 @@ void report_race(const struct unit *u, const char **name, const char **illusion)
 
 void
 report_building(const struct building *b, const char **name,
-const char **illusion)
+    const char **illusion)
 {
     if (name) {
         *name = buildingtype(b->type, b, b->size);
@@ -400,7 +400,7 @@ const char **illusion)
 
 int
 report_resources(const region * r, resource_report * result, int size,
-const faction * viewer, bool see_unit)
+    const faction * viewer, bool see_unit)
 {
     int n = 0;
 
@@ -487,7 +487,7 @@ const faction * viewer, bool see_unit)
 
 int
 bufunit(const faction * f, const unit * u, unsigned int indent, seen_mode mode, char *buf,
-size_t size)
+    size_t size)
 {
     int i, dh;
     int getarnt = fval(u, UFL_ANON_FACTION);
@@ -626,7 +626,7 @@ size_t size)
         skill *sv;
         for (sv = u->skills; sv != u->skills + u->skill_size; ++sv) {
             size_t bytes = spskill(bufp, size, f->locale, u, sv, &dh, 1);
-            assert(bytes <=INT_MAX);
+            assert(bytes <= INT_MAX);
             if (wrptr(&bufp, &size, (int)bytes) != 0)
                 WARN_STATIC_BUFFER();
         }
@@ -796,7 +796,7 @@ size_t size)
 
 size_t
 spskill(char *buffer, size_t size, const struct locale * lang,
-const struct unit * u, struct skill * sv, int *dh, int days)
+    const struct unit * u, struct skill * sv, int *dh, int days)
 {
     char *bufp = buffer;
     int i, effsk;
@@ -856,7 +856,7 @@ const struct unit * u, struct skill * sv, int *dh, int days)
                 WARN_STATIC_BUFFER();
         }
     }
-    return bufp-buffer;
+    return bufp - buffer;
 }
 
 void split_paragraph(strlist ** SP, const char *s, unsigned int indent, unsigned int width, char mark)
@@ -927,7 +927,7 @@ void lparagraph(struct strlist **SP, char *s, unsigned int indent, char mark)
 
 void
 spunit(struct strlist **SP, const struct faction *f, const unit * u, unsigned int indent,
-seen_mode mode)
+    seen_mode mode)
 {
     char buf[DISPLAYSIZE];
     int dh = bufunit(f, u, indent, mode, buf, sizeof(buf));
@@ -1013,7 +1013,7 @@ static void cb_add_address(region *r, unit *ut, void *cbdata) {
     address_data *data = (address_data *)cbdata;
     faction *f = data->f;
 
-    if (ut->faction==f) {
+    if (ut->faction == f) {
         unit *u;
         for (u = r->units; u; u = u->next) {
             faction *sf = visible_faction(f, u);
@@ -1140,8 +1140,8 @@ void reports_done(void) {
 int get_regions_distance_arr(region *rc, int radius, region *result[], int size)
 {
     int n = 0, i;
-    
-    if (size>n) {
+
+    if (size > n) {
         result[n++] = rc;
         fset(rc, RF_MARK);
     }
@@ -1151,7 +1151,7 @@ int get_regions_distance_arr(region *rc, int radius, region *result[], int size)
 
         r = result[i];
         dist = distance(rc, r);
-        if (dist<radius) {
+        if (dist < radius) {
             region *adj[MAXDIRECTIONS];
             int d;
 
@@ -1223,10 +1223,10 @@ static void add_seen_nb(faction *f, region *r, seen_mode mode) {
         get_neighbours(r, next);
         for (d = 0; d != MAXDIRECTIONS; ++d) {
             region *rn = next[d];
-            if (rn && rn->seen.mode<seen_neighbour) {
+            if (rn && rn->seen.mode < seen_neighbour) {
                 rn->seen.mode = seen_neighbour;
-                if (first->index>rn->index) first = rn;
-                if (last->index<rn->index) last = rn;
+                if (first->index > rn->index) first = rn;
+                if (last->index < rn->index) last = rn;
             }
         }
     }
@@ -1370,6 +1370,9 @@ void reorder_units(region * r)
 
 static region *lastregion(faction * f)
 {
+    if (!f->units) {
+        return NULL;
+    }
     return f->last ? f->last->next : NULL;
 }
 
@@ -1387,14 +1390,14 @@ static region *firstregion(faction * f)
 
 static void cb_add_seen(region *r, unit *u, void *cbdata) {
     faction *f = (faction *)cbdata;
-    if (u->faction==f) {
+    if (u->faction == f) {
         add_seen_nb(f, r, seen_travel);
     }
 }
 
 /** set region.seen based on visibility by one faction.
  *
- * this function may also update ctx->last and ctx->first for potential 
+ * this function may also update ctx->last and ctx->first for potential
  * lighthouses and travelthru reports
  */
 void prepare_report(report_context *ctx, faction *f)
@@ -1408,8 +1411,8 @@ void prepare_report(report_context *ctx, faction *f)
         rule_region_owners = config_token("rules.region_owner_pay_building", bt_lighthouse->_name);
     }
 
-    if (f->age<=2) {
-        if ((f->flags&FFL_PWMSG)==0) {
+    if (f->age <= 2) {
+        if ((f->flags&FFL_PWMSG) == 0) {
             /* TODO: this assumes unencrypted passwords */
             f->flags |= FFL_PWMSG;
             ADDMSG(&f->msgs, msg_message("changepasswd", "value", f->_password));
@@ -1421,72 +1424,74 @@ void prepare_report(report_context *ctx, faction *f)
     ctx->addresses = NULL;
     ctx->userdata = NULL;
     /* [first,last) interval of regions with a unit in it: */
-    ctx->first = firstregion(f);
-    ctx->last = lastregion(f);
+    if (f->units) {
+        ctx->first = firstregion(f);
+        ctx->last = lastregion(f);
 
-    for (r = ctx->first; r!=ctx->last; r = r->next) {
-        unit *u;
-        building *b;
-        int br = 0, c = 0, range = 0;
-        if (fval(r, RF_OBSERVER)) {
-            int skill = get_observer(r, f);
-            if (skill >= 0) {
-                add_seen_nb(f, r, seen_spell);
+        for (r = ctx->first; r != ctx->last; r = r->next) {
+            unit *u;
+            building *b;
+            int br = 0, c = 0, range = 0;
+            if (fval(r, RF_OBSERVER)) {
+                int skill = get_observer(r, f);
+                if (skill >= 0) {
+                    add_seen_nb(f, r, seen_spell);
+                }
             }
-        }
-        if (fval(r, RF_LIGHTHOUSE)) {
-            /* region owners get the report from lighthouses */
-            if (rule_region_owners && f == region_get_owner(r)) {
-                for (b = rbuildings(r); b; b = b->next) {
-                    if (b && b->type == bt_lighthouse) {
-                        /* region owners get maximm range */
-                        int br = lighthouse_range(b, NULL, NULL);
-                        if (br > range) range = br;
+            if (fval(r, RF_LIGHTHOUSE)) {
+                /* region owners get the report from lighthouses */
+                if (rule_region_owners && f == region_get_owner(r)) {
+                    for (b = rbuildings(r); b; b = b->next) {
+                        if (b && b->type == bt_lighthouse) {
+                            /* region owners get maximm range */
+                            int br = lighthouse_range(b, NULL, NULL);
+                            if (br > range) range = br;
+                        }
                     }
                 }
             }
-        }
 
-        b = NULL;
-        for (u = r->units; u; u = u->next) {
-            /* if we have any unit in this region, then we get seen_unit access */
-            if (u->faction == f) {
-                add_seen_nb(f, r, seen_unit);
-                /* units inside the lighthouse get range based on their perception
-                 * or the size, if perception is not a skill
-                 */
-                if (!fval(r, RF_LIGHTHOUSE)) {
-                    /* it's enough to add the region once, and if there are
-                    * no lighthouses, there is no need to look at more units */
-                    break;
-                }
-            }
-            if (range == 0 && u->building && u->building->type == bt_lighthouse) {
-                if (u->building && b != u->building) {
-                    b = u->building;
-                    c = buildingcapacity(b);
-                    br = 0;
-                }
-                c -= u->number;
-                if (u->faction == f && c >= 0) {
-                    /* unit is one of ours, and inside the current lighthouse */
-                    if (br == 0) {
-                        /* lazy-calculate the range */
-                        br = lighthouse_range(u->building, f, u);
+            b = NULL;
+            for (u = r->units; u; u = u->next) {
+                /* if we have any unit in this region, then we get seen_unit access */
+                if (u->faction == f) {
+                    add_seen_nb(f, r, seen_unit);
+                    /* units inside the lighthouse get range based on their perception
+                     * or the size, if perception is not a skill
+                     */
+                    if (!fval(r, RF_LIGHTHOUSE)) {
+                        /* it's enough to add the region once, and if there are
+                        * no lighthouses, there is no need to look at more units */
+                        break;
                     }
-                    if (br > range) {
-                        range = br;
+                }
+                if (range == 0 && u->building && u->building->type == bt_lighthouse) {
+                    if (u->building && b != u->building) {
+                        b = u->building;
+                        c = buildingcapacity(b);
+                        br = 0;
+                    }
+                    c -= u->number;
+                    if (u->faction == f && c >= 0) {
+                        /* unit is one of ours, and inside the current lighthouse */
+                        if (br == 0) {
+                            /* lazy-calculate the range */
+                            br = lighthouse_range(u->building, f, u);
+                        }
+                        if (br > range) {
+                            range = br;
+                        }
                     }
                 }
             }
-        }
-        if (range > 0) {
-            /* we are in at least one lighthouse. add the regions we can see from here! */
-            prepare_lighthouse(f, r, range);
-        }
+            if (range > 0) {
+                /* we are in at least one lighthouse. add the regions we can see from here! */
+                prepare_lighthouse(f, r, range);
+            }
 
-        if (fval(r, RF_TRAVELUNIT) && r->seen.mode<seen_travel) {
-            travelthru_map(r, cb_add_seen, f);
+            if (fval(r, RF_TRAVELUNIT) && r->seen.mode < seen_travel) {
+                travelthru_map(r, cb_add_seen, f);
+            }
         }
     }
     /* [fast,last) interval of seen regions (with lighthouses and travel)
@@ -1697,7 +1702,7 @@ const char *trailinto(const region * r, const struct locale *lang)
         size_t sz;
 
         sz = strlcpy(ref, tname, sizeof(ref));
-        sz += strlcat(ref+sz, "_trail", sizeof(ref)-sz);
+        sz += strlcat(ref + sz, "_trail", sizeof(ref) - sz);
         s = LOC(lang, ref);
         if (s && *s) {
             if (strstr(s, "%s"))
diff --git a/src/upkeep.c b/src/upkeep.c
index 8494d7f25..c4a937a45 100644
--- a/src/upkeep.c
+++ b/src/upkeep.c
@@ -191,6 +191,7 @@ void get_food(region * r)
         int need = lifestyle(u);
         faction *f = u->faction;
 
+        assert(u->hp > 0);
         need -= MAX(0, get_money(u));
 
         if (need > 0) {