Rarune
From The Heretic Knowledge Vault
Rarune is (or at least was) the Rinkai ambassador to Tsuiraku. Elven ambassadors are supposed to drop by Tsuiraku every twenty years; the last time he was there, he impregnated Meji's Mom with the mass of cells that would become Meji.
He has not appeared in the strip yet. However, Sarine, who clearly doesn't approve of his cavalierly contributing to the pool of possible Errants, tried to find contact information for him on her return to the elven homelands, so it's possible that she'll be paying him a not-so-friendly visit.