Mutation Energy Not Enough

Ray slightly calmed his breathing, and after recovering for a bit, he looked at the next advancement for his skill.

[Ding, it is detected that the host has Ten Million Mutation Energy, would you like to advance skill: True Eyes (Divine-class) from Awakening II to III?]

He almost flipped on the spot. From ten thousand to ten million, was the second advancement going to be a million?

Ray's eyes immediately became thoughtful. He had already wiped out all the undead from this continent.

There were seven continents in total, which means six were left, and some undead remained in the sky and the ocean.

Even with all of them combined, he might not even reach a billion mutation energy.

What if he could wipe out all the undead but could only upgrade this Divine-skill, which was obviously not as good as the other Divine-skill?