Death delayed
The people complaining about the other characters reliance on Yoon Seo are kind of missing the point.
The tragedy of Yoon Seo’s story is that, objectively speaking, the other heroes relying on him and even the red flame guy were objectively correct. He knows this, and that’s part of the reason why he wants to die so badly.
We have more context so we know the mental distress Soon Yeos in but from the perspective of the characters in the story, he’s a hunter who choose to live undercover even though he has the power to save millions of people.
Sure he doesn’t owe anything to anybody in the story, you can view the characters as entitled for demanding too much of him but realistically speaking, he’s powerful enough that he CAN prevent all of them from dying. The weaker side characters aren’t wrong to rely on him because otherwise they will die and it is quite literally in his job description to help them.
Also not to mention, I’m sure the idea of Yoon Seo getting tired probably never even crossed the minds of the side character since all of them either 1) grew up hearing stories about Yoon Seo depicting him akin to manhwa Jesus or 2) are used to NOBODY getting tired due to the use of potions.