We all love flustered, sexually repressed, lowkey horny Felix, but consider: homme fatale Felix. He realizes that he can weaponize his sexuality and he's not afraid to use it - sexuality/sex is just a means to an end

It's the war and information is gold. Felix hates being called pretty, but men are stupid. He accidentally slept with an off-duty Empire soldier once and discovered fatal information that determined the course of their next battle. Felix was commended by Byleth for his discovery

Everyone: How did you obtain this information?

Felix: You all don't need to know.

Sylvain, definitely knows: _____;;;;

Byleth, also knows: Ah.

At this point him and Sylvain aren't together yet but things are *going*. Sylvain practically begs Byleth not to let Felix "infiltrate" (wink wink) the enemy camp again bcs "I'm the resident slut, not Felix!"

Byleth: But he's built for the job.

Felix: I'm also prettier.

(In the past Sylvain tried to impersonate Ferdinand but failed miserably, "That ain't Lord Ferdinand, that's the Gautier bastard!!" Took him a while to escape enemy's detection bcs he's BIG and RED, thank you very much)

None of the dancer!Felix nonsense... He dresses up in plainclothes, walks into the tavern, and works up his charm to lure any unknowing Empire soldier into taking him back to the camp/back alley/etc

Felix is pointy, but can excel at things he wants to be good at and learns quickly to be likeable enough. Out of his armor, he looks generic and inconspicuous - anyone can be a pretty man with long, black hair. Nobody misses him when he slips away, so he gets the job done