>>49545486He's probably someone from Sinnoh because the rest of the Diamond clan are.
He live close to where Pastoria would be, he has waves in his shaved hair and he serves Basculegion and is a built dude. His design doesn't really show it but I'm pretty sure he's supposed to be Crasher Wake. Palina is definitely primarily Burgh but she also has a bandana similar to RSE May's. Also, the two of them definitely ended up together so their descendants would also be related.
Adaman and Irida I'm pretty sure are going to be references to future characters.