I'm actually not convinced if that really is Marth, with him suddenly being voiced by a woman from the voice clips here:
http://www.nintendo.co.jp/3ds/afej/characters/chara9.html
Yes, I know that this VA, Yuu Kobayashi, is known for voicing young males, but it doesn't make much sense to suddenly change when he already had a well established VA.
Plus his build looks a lot smaller, moreso than what he was like in Melee/Brawl/Shadow Dragon.
And if this game were to take place after FE3, he shouldn't be so young looking to begin with.
Oh and before anyone rags on Krom's name, you should know that it's pronounced like Chrome.
--
SuperNiceDog smelled us all later.