Estinien is going to Solvunn, and I'd say the most notable things about him is that he spontaneously grew horns, claws, a tails etc in a draconic way and is running around with Relena.

Also, he's going to be making an attempt on Ambrose's life before leaving, which sounds notable to Ralston's interests. The Darkling is going to intervene so he probably can't get a clean hit on him (and while time is frozen it wouldn't have any effect anyway) but the murderous intent will clearly be there to anyone watching

Ultimately he won't persist super long, both because of Darkling making it difficult and because Relena will urge him that they don't have time for this right now.