The sandbag item allows you to attach any creature to it and continue hitting it without killing it indefinitely. During the Festival of Jure in Noyel, there's an unavoidable sandbag with a human attached.
It's possible to hang yourself using rope or decapitate yourself with a guillotine.
In the outcome of Pael and her Mom, Pael's Mom asks you to kill her. She will eventually get better if you keep giving her potions of cure corruption in Elona+
You can eat human flesh, but will usually suffer a sanity penalty. However, there's a possible mutation that allows you to eat it without any negative effects.
The outcome of the Pael and her Mom quest ends with Pael's mom asking you for help in comitting suicide in the base game. In Elona+ you can continue to give her potions of cure corruption and she will eventually heal completely.
One Etherwind effect has you addicted to potions and consume random potions from your inventory. In Elona+ it's possible to become addicted to drugs and tobacco.