some characters have undefined attributes. it is mostly harmless, but causes the game to access uninitialised memory.
imp has no:

petruss wives has no fighting skills, and they need them just in case they will get some weapons. also, petruss wife #2 "wields" a child, so she needs weapon skills from the start.
i propose something like

firstborn item is missing some definitions, so danger caluclation for petruss wife #2 is UB.
don't ask me how i found that. you don't want to know.
SPOILER ALERT. Click here to see text.
there seem to be a problem with mushrooms too, but i don't know yet what causes it, and if it is present in vanilla too. it is something with graphics data and animation (and i rewrote graphics subsystem, so it's hard to compare things there).
imp has no:
DefaultArmStrength DefaultLegStrength DefaultDexterity DefaultAgility DefaultEndurancei don't know what to put there. i mean, by which other creature imp was modelled? and i'm not sure that this is harmless.

petruss wives has no fighting skills, and they need them just in case they will get some weapons. also, petruss wife #2 "wields" a child, so she needs weapon skills from the start.

// taken from the housewife KnownCWeaponSkills = { 3, UNARMED, UNCATEGORIZED, BLUNT_WEAPONS; } CWeaponSkillHits = { 2, 50, 50, 50; } BaseUnarmedStrength = 200;in the main definition. "blunt" added for frying pans and rolling pins.

firstborn item is missing some definitions, so danger caluclation for petruss wife #2 is UB.
Category = MISC; FormModifier = 30; //k8: i don't know IsTwoHanded = true; //k8: why not?
don't ask me how i found that. you don't want to know.
SPOILER ALERT. Click here to see text.
a lot of debug printing and a lot of valgrind sessions with k8IVAN. then quickly checked if vanilla is missing those too.
there seem to be a problem with mushrooms too, but i don't know yet what causes it, and if it is present in vanilla too. it is something with graphics data and animation (and i rewrote graphics subsystem, so it's hard to compare things there).