Quest

[Xinfu]

Could I use in? (not on)

-__ these quests, the heroes were said to be on adventures.

The meaning is 'within' the process of quests, so I think only in is correct, and on is wrong. Do you agree?

[Rusty]

Either 'in' or 'on' works. To establish the meaning of 'within', use 'in' or 'within'.

'With' is also possible.

[Xinfu]

Excellent answer. Thank you.