The Zeron family from left to right:

Alphonse (Alpha) Zeron, Senri Xii Zeron, Lina Zeron and James Zeron.

Senri was adopted by the Zeron family when they found him abondend in an alley, he was very introverted back then but now he is comfortable around them, even if he argues alot with his older brother who he names Alpha. Which is a reference to the past when Senri couldn't pronounce Alphonse ( he always got stuck on "Alpho" which kinda evolved into Alpha). Naturally he always get weird looks, when he calls them his family, but these past years made him feel at home and he is loved by his parents and brother even with no blood relation.