To be fair, Emet is like... rude in a polite way, if that makes sense. But the super condensed nutshell is "ancient immortal sorcerer who has been destroying worlds to bring his own back". Although he doesn't tend to drop the destroying worlds thing on people without good reason or a lot of probing. Mostly, he tends to come across as kind of snarky, very Tired, and disinclined to give anything like a complete answer.