Detective Work.

One method he tried to bypass the need for the target's permission was to offer Legion-1 a deal when he went to rescue him from the stone skin Origin gods. He didn't need Legion-1's help to build the matter to energy transmission and translocation pillars, but he still asked for it because he wanted to give Legion an opportunity to cross him.

The project he asked Legion-1 to help with was very important. If Legion-1 had tampered with it, then he would be within his rights to retaliate. If Legion had spilled his secrets to others, then he would have the right to check their secrets too. Unfortunately, Legion-1 didn't take the bait. 

Then he tried again with Legion-7, but that ended in failure again. However, he still didn't give up. After all, their connection to the system still remained, and he had a sure way to bypass the restrictions after he became a world god.