Cursed Seal of the Covenant

The is a  developed by Tōshi Ashiya, after studying the  of his clan's mikkyō, as a form of insurance during his missions. This technique, initiated with a simple handshake, binds the target in question to the terms of a spoken agreement by placing a upon their hand. Under normal conditions this seal, in the form of a pair of snakes, is harmless to the one who bears it. Furthermore, the seal will naturally disappear once the terms of the aforementioned spoken agreement is successfully fulfilled. The true activation of the technique comes when the target in question attempts to break, or in any way undermine, the deal made with the seal's user. Upon doing so the twin serpent design with begin to spread up the victim's arm towards their heart, causing paralysis and inhibiting chakra flow along the route. Should the seal reach its destination the same effect is inflicted on the heart itself, imparting a lethal consequence for breaking the pact. On average the completion of the curse takes roughly an hour, with differences in duration stemming from the size of the target in question.

The progression of the cursed seal can be delayed through the use of secondary, but outside of its complete removal it will continue to move towards the victim's heart. To that end the can slow the spread of the curse to nearly a day. Additionally, the curse's crawl towards the heart can be effectively stopped by severing the entire afflicted area from the body. It should be noted that Tōshi can remotely remove the seal from the target at will, which he has demonstrated when the original agreement no longer fits the scenario at hand.