Black Lightning Seal

The Black Lightning Seal is a Fūinjutsu that is considered exclusive to the Inazuma Clan. It is typically placed on the left or right shoulder of a clan member, with the appearance of the Inazuma Clan's mon, a modified '雷' symbol. Through its use, members of the clan can perform techniques that utilize Black Lightning, although how it achieves this is unknown to most. Even among members of the clan itself, only a very few including the leading family know the secrets behind it.
== Use in Role-Play ==
Although the mechanics of this seal are not known in-character, and not explained outside of it, the idea of how it is meant to work can still be used by members. Over time, this seal stores up a form of energy that is used when performing techniques that use Black Lightning. This seal directly interacts with a character's chakra reserves, and uses it to perform said techniques. Because of this, how much this seal can store is dependent on the size of a character's chakra reserves. To represent this, how much energy is stored by your seal is exactly ½ the value of your character's Chakra attribute. Although the resources of this seal are finite, they can be replenished over the course of a day or through other means specified by a WM.
Similarly, the same concept is applied when the cost of a Black Lightning technique is brought up. Instead of it being purely chakra, its cost is split into two. Half of it will consist of your character's chakra, while the other half will consist of the energy stored in their Black Lightning Seal.