Contract

『Contract』is a binding force created by the God of Covenant, in which a party of at least two people vow to uphold mutuals promises. Whether it be to exchange things, buying and selling, or even do something in exchange for information.

Overview
A『Contract』enforces a promise that was made between two consenting individuals. As far as is known, once two people are determined to make a『Contract』one must show a medallion to exchange vows to keep a promise, while the other must use an pendant to which will reaffirm the promise, once both items are connected with a bright light the 『Contract』 will start.

Taboo
It is stated that if one breaks a『Contract』, that one will be affected by the "Curse of Insomnia". At first, it will happens once a week; then once every few days; until in the end, each day would be a nightmare without sleep. No matter how much you want to sleep, it just won't be possible. Even if your head is in a daze, even if your consciousness is blurry, sleep will always be out of reach. If after all that, you still don't keep your end of the bargain, it can even lead to your death.