(Eric/OC) Tobias leaves more behind in Abnegation than just his father. When his little sister follows in his footsteps, he does what he can to keep her in Dauntless, and out of others' hands.
Xedalia Trammers was born in Erudite, where her personality (apparently) does not match up. Her decision to live as her true character causes her to live a true life; to lose people, to gain friends...