Nathan absorbed the lower-level cores first. The elite class cores were the most important and gave much more energy, so it was better to absorb them after he increased his quality.
Unfortunately, after absorbing all the cores, he didn't see any increase in his quality.
It was quite disappointing, but it couldn't really be helped. Still, thanks to the manual, by the time he finished absorbing all the cores from the proto-class to warrior class mutant cores, his ena had gone from 5 million to almost 13 million.
It was more than enough for him, but to become a crystal fusion, one required several familiars to be on this level.
However, Nathan's familiars were divine beasts. Even if they didn't have 10 million ena, their fighting power would be close to a normal familiar with 10 million ena thanks to their divinity.
So, just by having him reach this threshold, he could be counted as a world class summoner on Gratzel, unofficially, of course.
