Mana amplification's might

Seeing him attack, Derek laughed in anger.

A murderous glint flashed in his eyes and a sneer crept up on his face. He then activated his skill [Power Burst] which immediately doubled his physical strength.

"Die!" Feeling the power coursing through his body, he shouted out and swung his axe at the incoming sword with all his might.

He wanted to break the sword and hack Luke into two pieces with this attack. 

With his 40+ strength, it would have been easy to accomplice this, but what actually happened sent chills down his spine.

When Luke sensed the sudden increase in Derek's power, he knew he must have activated a powerful spell.

'Perhaps I should use some more mana?' Luke thought. 

Since he wanted to finish the fight as soon as possible, but Derek was quite strong, when he attacked, he had activated his newly gained [Mana enhancement] skill and covered his sword with five mana units to finish him off in one strike.