Aeson is the disappointing younger brother, despite his older siblings' foibles and his own merits. He's a layered person, who wears so many masks to protect himself even he frequently doesn't know what's really him and what isn't.

Older phase is much more jaded and has much deeper masks, and doesn't let himself get close to anyone.
Younger phase is bitter and arrogant but usually does genuinely want to do the right thing - mainly because his core self is usually less covered.