not for fell drain, just for delivering them with autohitting magic missiles. I'm not aware of any cheap counter to fell drain. Again, apart from being a Warforged
edit: Sunstroke was in Sandstorm I think, what did it do again? Something like damage+status effect, though it was some kind of heat damage described in Sandstorm, not fire. No idea if Resist helps, take that to the Waiting Room if you need a clear answer