Is soul drain the best combat spell in the game?

[Endoperez]

If fatique raises above 200, it gives damage. The big spells would be uncastable by mages that meet the power requirement, as they would need to have lots of extra gems and be able to use them (only [magic level] gems can be used per turn, so with spells needing lots of gems it might be impossible to use extra gems with the minimum required level). I don't know if this is good thing or bad thing, or even if this is the reason, but I think it is.