Fin Fennec is the locked room instructor at BLUE and the world's expert on locked room studies.

She is one of the few people in the world who holds a S-rank detective license. With her "Phoenix touch" ability, she has found 5,000 hidden rooms, 3,000 illegal constructions, and 10,000 tricks of physics so far.

(Source: Ron Kamonohashi: Deranged Detective Wiki)