Parasite-type Zanpakutō

Parasite-type Zanpakutō (寄生虫型斬魄刀, Kiseichū-kata Zanpakutō) are a unique type of with highly destructive properties. Parasite-Type Zanpakutō are unique in the fact that they act as they're named. Consisting of draining raw energy in exchange for power, Parasite-Type Zanpakutō act as leeches on the wielders on spiritual and physical energy. The prolonged usage of a Parasite-Type Zanpakutō has proven in the past to have catastrophic results, to the point where a life is taken in exchange.

Those who have mastered their Zanpakutō, have proven to utilize their ability to commune with their Zanpakutō's Spirit to create a "pact" that allows them to evenly exchange their energies for power. This heavily changes the fundamentals of a Parasite-Zanpakutō, effectively turning it's weakness into a strength.