Orc Empire.
Watching the neighboring territories prosper while dealing with an internal war on one's own lands can make anyone uneasy.
Similarly, the Four Royal Families felt even more anxious. Unlike the Alliance of Seven Clans, which had no choice but to fight to the bitter end, these established beneficiaries had much more at stake.
Plans never keep up with changes. The plan to divide the Alliance of Seven Clans was successful, but the plan to disintegrate it failed.
The act of "Six Peaches Kill Seven Gentlemen" could only sow doubt among the Seven Clans, but it's hard to break their unity when they are bound by contracts.
Magic Contracts are so useful, yet their widespread adoption is limited, partly because of high costs and partly due to fears of tampering.
For cases like the Elf Race and Alpha Kingdom where both sides have Sanctuary Powerhouses, ensuring that neither side can fiddle with the contract, that's a different story.