Goblin Slayer - Angry bois

his comparison to Doom guy is only superficial.

I would say a better comparison is Batman.
-Witnessed the death of his loved ones as a child
-Vowed vengeance on the assailants
-Is only human but is highly skilled in areas necessary to his quest
-Works alone but accepts help when it is appropriate
-Is arguably insane but in a benign and largely beneficial way
-Feared and misunderstood by everyone
-Has a kind heart under his cold personality

That's the joke.