The Demonic Way is full of deceit and scheming. Even when collaborating to deal with the Buddhism School, the cooperation is always limited and never without reservation.
So, even though he got the other Demon Monarchs' promise to act, the Ten Thousand Beasts Demon Monarch actually always held back, not going too far.
Because he cannot be sure if there was really a war with Buddhism, whether the others would truly support him, or if he would be abandoned when necessary.
Therefore, even when ambushing Mahasthamaprapta, the Ten Thousand Beasts Demon Monarch didn't give his all but kept a bit of strength in reserve.
Because he needs to ensure that he always has the power to counter, in the face of Buddhism's potential retaliation, he wouldn't have to completely rely on others. He must have the power to protect himself.
