That's likely Ooi's hand and skirt in the right border of the image, but I'm not 100% sure -- only 99.9% sure, and even that is more because of meta knowledge about the two of them than the fact that the sleeve and skirt's colors match.
Then they twirl around while holding hands, throwing out torpedoes.
Oh, I know about their battle dance, spinning around in circles and giving the Abyssals an epic case of "torpedus".
What I DON'T know is if someone who knows absolutely nothing at all about Kantai Collection except the characters' names and likenesses would be able to tell that it's Ooi on the right by nothing more than her left hand, sleeve cuff and skirt hem, and that's why I am hesitant to add the tag. The fact that Ooi is out of focus and thus slightly blurry does little to help.
