Each time an individual player retires a character, that player also gains one extra perk to apply to all future characters they create.
This effect is cumulative, so when a player retires their second character, his or her next character would gain two additional perks.
Though this effect is applied to players, if one player is controlling multiple characters at once in a campaign (e.g., solo play), he or she considers each character lineage they control a different player for this bonus.