Undoubtedly, those leaders would never commit to anything uncertain. Thus, upon learning of the Blood Moon Lord's response, they were left with no choice but to cease fighting.
Of course, if two leaders were to combine their forces, they could potentially pose a threat to Zhou Tian and his group. But the current issue is that such a situation is believed to be next to impossible. All the forces on the continent are now in a delicate balance. Although the leaders have personal connections with each other, it is difficult for them to unite against Zhou Tian. The reasons for this are twofold: one, the allocation of benefits is problematic, and two, if the other leaders can find support, why couldn't the Blood Moon Lord?
Given these factors and their inability to pose a serious threat to Zhou Tian and his group, no leader would risk their own safety for a battle outcome that remains uncertain.
