Leonardo is a mature man. Though he uses humor to cope, hes much smarter, and adjusted for the Kraang apocalypse, now. He's very tactical, and good under pressure. He can come up with things on the spot, very good at improvising. Hes very quick witted. 
He'd do anything for the family he has left, and will protect them, until his last breath. 
He has mystic powers, along with a mystic portal summoning swords.
He has one sibling left, Michealangelo.
Donatello and Raphael died in the Kraang war. 