(in) the devil
Used as an intensifier after a question word (who, what, where, when, why, and how) to express extreme confusion, surprise, or aggravation. And just how the devil am I supposed to have three reports done by 9 AM tomorrow? Where in the devil did you find that rusty old car? Who the devil is making all that noise?
the devil
1. Particularly difficult, arduous, or unpleasant. My husband's handwriting is the devil to read. This cake is always the devil to get out of the pan, so it always ends up looking like a mess by the time I'm done.
2. The brunt of another's anger, scorn, or wrath. Usually used after the verb "catch." If I get home past curfew again, I'm really going to catch the devil from my parents!