at first i was thinking this has to be a ohma double but then again the author has been showing fighters replaced by doubles the whole manga, and the guy that stole the dna is the enemy so he's acting or actually surprised to see these guys. Plus if anyone was going to save ohma it'd be the kure. The twist will probably be this is the real ohma, while koga gets replaced by a double. Unless we see him get out from his situation without a time skip. We'll know as soon as ohma and koga meet since a koga double likely wont know about his grudge towards ohma.