Most source beast masters would use a secret technique to fuse with their own source beasts. Even though their own source beasts had given up on the initiative, they would still exist. Moreover, some of the source beasts would cherish their own bodies. Thus, they would not allow their own source beast masters to engage in large-scale battles. For example, when a source beast engaged in a battle with the other party to deal some damage, it might even focus on fusing with its own source beast with a destructive technique. After that, both parties would separate and carry out a failed secret technique fusion.
When their master fused with them, the source beast would see that their master was using their body to fight, and some of them would even send out a message. It was certain that not every source beast was willing to fuse with their master. As free beings, they did not want to be controlled by others.