Rein was the first one to make a move. He used his usual boost and clad his whole body in crimson lightning and golden light and charged toward the armoured person. At the same time he utilised his Eye of Truth to find a gap or flaw in the final boss' defence.
But unfortunately for Rein, this person was truly worthy of its incredible strength as there was absolutely no gap in its defence. But still Rein started to exchange blows to create flaws if it did not have any.
As both of them started to clash swords, they soon entered a special mystical state where they forget about anything but each other. It was as if they were inside their own little world.
Rein had never learned swordsmanship from anyone and the style he used was something he had developed himself after fighting hundreds of millions of opponents throughout all of his lives.