Memes

Megumin's other problem is she only specced into things that would improve her explosion's damage output, neglecting basic mage things like mana capacity and efficiency. So she can only cast one (stupidly overpowered) explosion spell before all but passing out from using more mana than she actually has. It's why no other party would take her, because even in situations where the spell would be useful she becomes a massive liability after casting it.