Battle against Immortal (Part 2): What is this?

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When Shin saw that Immortal had used one of his berserk skill, he knew that he could make a change only if he increased his speed to the limit. That put him in a dilemma. He was forced to consider whether he should use the current best moment speed enhancing skill or the 'Mondi's Movement Legacy Skill'.

As a matter of fact, he could use the other moment speed boost from his other set, but that meant he would have to give up the berserk skills and domain skills that he currently possessed. It was because, switching out the equipments and weapons that he currently wore, would result to the deactivation of the item's buff skills. He could only add on to the current equipment set that he was wearing at that moment.