Greak: Memories of Azur

It's better to beat him solo (leave your sister at the top). The boss has three attacks - a ram and a jump with a blow to the ground. There is a ground slam without jumping if you are within striking distance. It’s easier to dodge attacks by rolling into a strike.
From the middle of his life, he begins to become Satanic and makes three blows at a time - three rams in a row or three jumps in a row. In the second half of the battle, it is better to be closer to the middle of the arena.
You can beat this boss without taking damage if you understand exactly when it is most profitable to hit him. A touchstone can also help if you take it with you. It will increase your damage a little and beat the boss a little faster.