The Dog Was the Mastermind: Selim Bradley, the seemingly sweet and innocent adopted child of King Bradley, is actually the first homunculus created by Father, Pride.
Even Evil Has Standards: According to Winry, Kimblee sincerely expressed admiration for her parents and their personal sacrifice in the name of what they believed. Granted, this could be a case of Kimblee keeping up appearances, it's rather in-character that as opposed to his disdain for hypocrisy, he admires people who are willing to die for what they believe in, even if those beliefs may clash with his own.
Evil All Along: Selim Bradley is revealed to be the homunculus Pride, whose innocent child personality was all an act.
Exact Words: Selim/Pride claims he was the First Homunculus. This is technically true; he is the first Homunculus... or rather, the first Homunculus created by Father (who is the true first Homunculus).
Dramatic Irony: Not only is Winry unaware she's a hostage in the whole Homunculus Conspiracy, but she doesn't even know what kind of monster Kimblee is, especially when he respectfully admits he admired her parents for their beliefs.
Five-Second Foreshadowing: When Hawkeye is speaking with Mrs. Bradley, a familiar set of shadowy tentacles sneak up on her, alerting her and the audience that whoever she sees is the Eldritch Abomination lurking in the tunnel under Briggs. It's Selim Bradley.
Love Epiphany: While trying to warn Winry not to trust Kimblee, Ed remembers Hawkeye's recount of the Ishvalan Civil War, which Kimblee participated in... as well as Hawkeye asking him if he is in love with Winry, and realizes that he really is. Hilarity Ensues!
Not So Similar: Hawkeye admits to Pride that she already suspected his Homunculus nature at some point because when he snuck up on her earlier, she sensed the same bloodlust from when Gluttony tried to ambush her from behind. ...but then she back tracks as she notes that unlike Gluttony, Pride is driven by a sort of pressure. Even Pride casually remarks how he's offended that Hawkeye compare the two Homunculi.
Wham Line: When Mrs. Bradley mentions that Selim was adopted from her husband's relatives, this tips off both Hawkeye and the audience that Selim is something else if he's adopted from relatives who don't exist.
