So I'm guessing Archer is saying something about Waver joining the harem protagonist club, with all the characters from CF as love interests: four students, an imouto-chan who is also a student, and a couple people actually his own damn age. And... Waver, as usual, is pissed off because he feels made fun of.
PupilAdoptive Younger SisterMen (too)A threesome is fine too <3Student (uninvited)Student (Wishes to become a Mistress)Beauty of FateWhat's with that face that says you've found a comrade!? Don't lump me in with you!!