Board Thread:Roleplaying/@comment-26103034-20161223122300/@comment-5262726-20170104052718

(Same reason the Dragonborn did. I could explain it better with a dip in morals and a higher interest in power, followed by repentance (The Hero redid the pilgrimage and purified his name once more, and the Dragonborn joined the Dawnguard, rejected the gift of Vampirism, thus putting morals over power, and destroyed the Volkihar Clan, then saved Solthseim from Miraak, thus seeing what an obsessiveness over power can do to somebody.)

Recite the Five Tenets, recite the plea from "A Kiss, Sweet Mother," summon Lucien Lachance and have him vouch for me, etc.