Conjurer was the one that resulted in the creation of the System World. Basically, he had seen the entire growth of the Systems and realised the tremendous potential they possessed.
After all, the race of Systems currently was a conglomerate so vast that the entities on the level of Immortal, Magister, and even Mystique had no other choice but to team up to fight against them.
It had to be noted that there was a time when Conjurer had no other choice but to pander to the whims of Magister, an existence too strong for him to even think about going against. Which is why he supported the Systems.
Of course, the world he created wouldn't be that simple. Mental Fragments were simply building blocks of a System's body, one that could exist in reality without crumbling apart. That was what Conjurer had been researching up to create until now and had already achieved.