do I need to keep Demenion alive for a quest?

[loreangelicus]

Just rounding up the path Debir-Scarlet-Bolo-Verona-Rusty-Scarlet-Debir-Verona-Montero-Verona; my question is, do I need to keep Demenion alive to complete a quest later on in the game? Is there a bounty on his head? Do I need him alive to complete the Demenion's Secret quest?

So far I have gotten 2 out of 2 Ancient Knowledge scrolls from Elenhel via the replay-battle-differently trick. As such, I decided to start using AKs killing the heroes of Montero and Verona (at least those that would end up giving me 6,000+ XP with the AK scroll on) since I may have a surplus of it if Elenhel keeps giving me AK scrolls every 30 battles. My level jumped up quite a bit, allowing me to take out all heroes at Montero and Verona (even the Driller).

So is it ok to kill Demenion this early (see attached screenshot)?