I made this in the Robin support thread, so I might as well share it here.
My ideal choice for a Fire Emblem newcomer is Validar, provided that there's more to FE: Awakening representation other than Arena Ferox, adult Tiki, Robin's theme
and Chrom.
When he is summoned, Validar appears from within an aura of dark magic, laughing menacingly. Validar casts a teleportation spell, moving himself across the stage to the nearest enemy player. His main attack is the spell Nosferatu, dealing 10-30% damage with little-to-no knockback, healing the summoner with the exact same amount. He will proceed to do this for about three times, before finally disappearing.
I imagine that he would be somewhat easy to avoid, but chances are at least one player is going to be attacked, especially if he's a small stage.
If a player who isn't Robin summons him, he'll say "
You cannot escape fate!". But if a Robin player summons him, he will say to him/her, "
As you command, my liege…"