Tendou is a beta right ?

I think so too!

he's an alpha

Give up already. He is an alpha. Reread from ch 1. That's why kadota couldn't punch him when the pair was made. That's also why kazuomi being blackmailed by tendou to get get bitten if kazuomi refuse to had sex with tendou

Ah ok, I don't remember the first chapter, but it's a shame if we can't see what happen next.