Why?

BANNGG

A fireball hit The First's shield and exploded. Flames burst out and engulfed the area. Still, the flames couldn't burn The First's shield.

'I don't know what is going on between these people but I should fight...'

Wondering about the man's identity wouldn't help at all at the moment. Kairen could ask Kain or Reyan or even Glenn later. 

Kairen cast multiple spells at the same time. Now that he had learned how to remove the extra and unwanted parts of a spell, he had more than enough mana to do that.

The First, dodging the attacks one by one and counterattacking at the same time, looked at Kairen before raising his empty hand that was not holding his sword to the air.

ZAAAAP

Something flickered on his palm before a shiny transparent blade pupped up out of nowhere. 

No, it wasn't actually a blade, but a condensed form of aura that only swordmasters were capable of controlling.