My absolutely favorite. You really hit it on the head what makes him so... interesting and good. He's so fascinating and I love him. :)
XanderFire Emblem has no shortage of memorable characters but none of them hit quite like Soren. His pragmatic, cynical nature contrasted with his fierce loyalty to Ike, and his self loathing of his own lineage feeding into how he treats others. Soren feels real to me moreso than any other FE character.