I don't think he's under oath or contract.
It was probably that they knew of his kind disposition, as well as his intention to kill himself after he got out of the "Great Dungeon".
They intended to leave wills to him in order to prolong his attempt until he finds happiness or reason to live.
Thankyou so much, i was so curious that i skimmed through the novel chapters but couldnt understand the translation nor find out that part. Thanks alot ^_^
You're welcome.
In addition, MC actually slightly mentioned that he knew their intentions to stop him. But it still puzzles him why they have to do it to him.
Is he under an oath/condition/contract where he has to fulfill all the wills of the dead comfade? Or is he just doing it for his own personal satisfaction and guilt?