It making sense that he isn't ML.
In first TL he basically helped to kill off MC and his family, just so he can be the aura stone master (not knowing that is it's master killed off, the aura stone just turn back the time).
And in current TL he went on the same way, and only after having saw the past life, knowing that there is no way for him to became the master of the aura stone and he betrayed by the people whom he helped until now decided to help MC.
I wouldn' be able trust in a person like that.

I would have liked it more if the grand mage were the ml