use of king prisoner and the sabotage task

[wailoktam]

Hi, I wonder what's the benefit of keeping him as a prisoner or let him go. Assuming that beheading reward you nothing. Also, I read there is a sabotage task in monteville. How can I get it?

[ckdamascus]

Hi, I wonder what's the benefit of keeping him as a prisoner or let him go. Assuming that beheading reward you nothing. Also, I read there is a sabotage task in monteville. How can I get it?

If you keep all the kings as prisoners, you can trade them for 1 experience level to the demon king on sandy isle (I think).