Xexilf
Oblivion Sempiternum Daemonis
IIRC theres a third, but its even more out of reach.Technically, Solars get two cap-breakers; one that lets them buy an extra dot of Essence, gaining its benefits on activating the charm (and flaring totemic and eating a bunch of Limit), and one that reduces the minimum Essence and Ability scores for Charms in a given Ability by 1.
If the unconquered sun dies, every solar gets one essence + instantly (as well as hatred of whoever did it). In theory this is ever repeatable if a new Sun is appointed, i think.