The next day, Karin and Sez was a fisherman who was overpowered by the waves. This brings together Karin and the Phantom CIC for an unforgettable summer ...
Seaside Bellona will be available to players via summons beginning on 8/1. Basically it means re run banner, you not only get skin, but also a hero. I also heard rumor about Sez skin.
Looks like skins doesn't bring stats or skill change, only animation changed.
Full information about update.