Why did NPC in secret area in chapter 4 dispawned after i beat BOSS!?

[Delete]

So there is a Monk asked me to find maggots, but after that i randomly stumbled at BOSS and beat it, after that NPC is gone, even if i have requed item.
What so critical in removin that NPC!? Now i have one unbeatable BOSS because of that, god i hate skipable content that doesn't even warn you in any way it can be skipped.
Fix this, spawn him back and let me beat his.....anything

[Wini]

maybe he by a another location where you did not see it

[Scorpion]

I am a victim too... If you killed Duskveil, this quest will be gone. But hey... ng+ then... which I am playing now because, there are new weapon unlock tiers...