Complex sentence: He wields a regalia of wind that, in combination with Hannibal's water regalia, creates powerful ice attacks and uses this skill to freeze the people of Owari to serve as hostages.
Split into simpler sentences: He wields a regalia of wind that, in combination with Hannibal's water regalia, creates powerful ice attacks. He uses this skill to freeze the people of Owari so that they may serve as hostages.