[HEAVY SPOILERS] I've been thinking, we have characters representing pretty much all possible endings, no?

Savan completed all the trials and became the Seneschal

Grigori beat the Dragon but lost to the Seneschal then himself became a Dragon

The Duke took the Dragon's offer and sacrificed his love for power

The Dragonforged fought the Dragon and lost/ran away (I think)

I think Selene's Arisen may have been a Seneschal who used the Godsbane?

Now for someone who took the Seneschal's offer and returned to a peaceful life... Could be anyone, I guess.