Responses

Theo's secondary gender has not been revealed. It's highly unlikely that he's an omega. In both the two series, it's been pointed out that the only role omegas are allowed in the Seigfried household is to breed more beasts. Even Kai was going to be put into that role before Ruado bonded with him. And Baron practically laughed at Daato thinking he'd be a servant.
Read Ruado's story, want Juda's story..
Read Juda's story, want their parent's story..
What next?? ╮( ̄▽ ̄)╭