League of Kingdoms

United we stand, divided we fall -League of Kingdoms motto

League of Kingdoms was originally founded by Bryten kingdom, and to this day is informally lead by Brytens, though not many would admit it.

Formally, it is an alliance of human kingdoms and Elves. Their main goal is to maintain peace and provide some basic rights and freedoms to citizens of all kingdoms. While they rarely enforce laws and regulations, when they do, they mean it. This, for example, includes various laws regarding magic passed on by Elves or the legendary Treaty of Turrimton.

They also act as a neutral judge for international conflicts and they oversee various deals and contracts. While most of the heavy-lifting is done by Brytens and most meetings take place on Bryten soil, the League itself remains neutral.

Officials and other staff of the League are hard-working fellows, and they understand how fragile the peace is. Had it not been for them it would have all fallen apart long time ago. The League has prevented many wars and continues to do so. Maybe this is why elves trust the League (when they generally do not support humans).

Specialty

The League is fairly competent at keeping the nations out each other's hair. They can defuse most conflicts between human kingdoms, and aid Elves if they deem it necessary to intervene (which is fairly rare, but it does happen once every other decade, give or take).

Outside of diplomacy, they also offer aid, gold and other resources to provide disaster control or emergency mitigation.

Lastly, they prosecute some high-value criminals, or track-down some materials and contraband if it is deemed a threat to the peace, although this is usually done by calling in The Inquisition.

That being said, it is almost impossible to get the League to act in a specific way. Gold and power are not terribly effective... Your best course of action is probably to demonstrate that given situation is serious and poses a significant threat to the peace.