After they became legendary slavers, they gained the Power Bond divine ability. This is a powerful divine ability useful for enslaving people and gaining power from them.
Not only does this divine ability make Legion excited, but it has come at a good time because enslaving other godclads will become more and more difficult from here on out.
The difficulty in enslaving a legend lies entirely because of their state of existence. The special state of existence of legends makes them capable of liberating their divine form. This means that they aren't exactly humans anymore.
The body of legends has changed so much that it is mostly divine flesh. This divine flesh forms a protective cocoon around the souls of legends.
This protective cocoon is what manifests as their divine form and grants them great power. But even in the dormant state, the cocoon of divine flesh protects them and rejects everything that is not part of their body.
