It's been a while since I've played FE: Heroes, so I forgot if the summoner has to have special qualities or not. But in terms of the whole "summoning and bonding with heroes" type, I imagine Shadmé would have it rough! She's not magically gifted, first off. And second, she comes from the Kid Icarus universe, where a certain known gaming angel has gotten her into video games, and it would break her heart to summon Marth or Roy or something only for them to be torn away from her. XD
Which OC would have a difficult time trying to explain Earth (or whatever their world is) to a visiting alien?