I have this crazy idea, about the DLC, because there's a question that ran through my head..... why did they choose Marht, Ike and Alm instead of Sigurd for example ?
I think I have this theory to explain it.
Marth : it's no brainer he is the first Fire Emblem hero and the mascot of the series,secondly the game is based in the world of Marth.
Alm : Awakening borrow the map system from Gaiden. and Varm= Barensia
Ike : Awkening is 3D and Path or Radiance was the first 3D Fire Emblem game , Krom resemble Ike in design very much he even gets Aether as a skill.