The robot has a Rockbell Engineering maker's mark on it riding the opposite shoulder of the snake-and-cross brand. The sight the first mark makes some people nod, others whistle - a Rockbell robot is pretty expensive and how can that kid afford a robot that size?
There are people who know the truth - it isn't a robot. He isn't a robot - he's a boy, a young teen now, a human soul wrapped up into that metal skin. A functioning A.I. - something that shouldn't have happened. Something improbable. Something impossible.
Edward Elric, the kid in the red coat, is a genius who wouldn't let his brother die. He used ancient lore, something they called 'alchemy', something they called 'witchcraft', something ancient and arcane and powerful. Somehow, he managed to capture his brother's soul as it left his body, taking it and his personality, his memories, everything that made Alphonse Elric 'Al' and managed to stuff it to an antique suit of armor.
He's lucky - robots are the mode now. All the best people have them. And Pinako Rockbell is happy enough to put her mark on the armor to continue the ruse - help keep both of the brothers safe.
"I'll figure out a way to get your body back," Edward says to Alphonse, tapping his metal fist on the chest plate, making the hollow space inside boom softly.
"I know you will," Alphonse says, because he has to keep his brother's spirits up. Even if he's not sure it will ever happen.
Even if he remains an iron giant for the rest of what will be his life.