After all, for Mansour, a plan for transcendence must not be allowed to be disrupted by others.
For Milton Cheney, Mansour was a variable, and it goes without saying that for Mansour, Milton Cheney was also a variable.
Wanting to become a Transcendent before Mansour, Mansour was inevitably an influencing factor that could not be avoided.
As for secretly achieving transcendence without Mansour's knowledge, that was almost impossible, after all the Wizard Realm was only so large, and Milton Cheney's method of transcendence was still to transform the Wizard Realm into his Witch Immortal Divine Land.
Under such circumstances, it was impossible for Mansour not to find out.
Of course, even if Mansour discovered Milton Cheney's intentions and intervened to stop him, preventing Milton Cheney from becoming a Level 7 Wizard Immortal would definitely not be easy.
What's more, Milton Cheney had a backup plan.