Of course.
The main reason was that Lake was still thinking that, if he got the chance, he wanted to subdue Mephisto rather than simply chop him to pieces.
Lake was willing to delegate authority.
That was also why Lake had handed the authority over the sea to Star-Lord so easily. Part of it was because he did not want to waste too much time on Ego, and part of it was because he felt Star-Lord was naturally his man and someone with potential. But more importantly, Lake wanted to give himself more free time.
After all...
Lake had created the Chaos Force Universe from the very beginning not with the intention of ruling it, but so that he could do whatever he pleased without anyone being able to threaten him.
There was a saying.
It was easy to conquer the world, but hard to sit upon it.
Lake deeply agreed with that.
So, to avoid becoming like Odin after conquering the world—clearly immortal, yet ending up with a head of white hair because of endless trivial matters—Lake chose to delegate authority.
In any case, the Chaos Force Tree was always under his control. He was the source of all power from the Chaos Universe. Even if someone wanted to rebel, they would first need the soil for it to grow in.
Lake sincerely hoped Mephisto would become the King of the Underworld and help shoulder his burdens.
However, Lake knew that such an idea had basically lost all viability now.
Forget it.
Let it be destroyed.
Lake did not want to go further and further down the road of recruiting Mephisto. Enough was enough. He had given Mephisto so many chances. Although most of what he had said had been jokes, Mephisto had not taken a single one seriously.