Bab 1258: The Time Worms.

These three divine abilities are very powerful. Unfortunately, Legion-5 can't use them. This is because of his dragon heart. Lightning is highly destructive so it doesn't go well with regenerative divine abilities. 

It would have been a perfect combination if there was lightning hydra. Unfortunately, there isn't. In fact, lightning is one of the weaknesses of Hydras. They can't heal injuries created by Lightning. So assimilating the Life duplication divine ability of Hydras with his dragon heart is asking for trouble. 

While Legion-7 can overcome the resistance of some divine abilities to his dragon heart without destroying their function, they won't be able to get enhancement between the divine abilities if they are not compatible. 

If they want to fuse a divine ability with the dragon heart and they want them to amplify each other, then it must be one that must work with lightning. This narrowed their options for recovery divine abilities to two.