Hone Hone no Mi/Marrow Shift Techniques

Marrow Shift (Marō Shifuto) is a technique developed by Buster D. Zack through the use of his Hone Hone no Mi, which allows him to increase his physical prowess such as speed and agility. Zack used to refer to the technique as Super Exo.

Overview
This technique is one of Zack's most "in-depth" creations. By manipulating his bones, lowering their density Zack is able to increase his overall mobility to the point that he can appear as but a blur when he moves to those of lower combative prowess. By the time he had battle Velour Sasha, he could only lower his bone density by ten percent, however at Wildweyst Island, he was able to do it by fifteen percent which he states is his limit. While he can gain a speed increase in this state, Zack's durability is decreased to noticeable levels. Simple punches and blows are enough to knock Zack down to the point he needs a bit of medical attention. His first time left him in a state to where he could not even stand on his feet, though further uses of it allowed him to become more resistant. He even suffered severe damage from a bullet wound that would normally not even pierce the bone, when he was shot by Connors Chuck.

It should be noted that only someone who has an understanding of the skeletal system would be able to achieve a form, as Zack is part-time pre-med who learned under Thatch Vincent while he was a Cabin Boy on Daddy L. Legs ship.

Usage
Zack activates Marrow Shift by crossing his arms in front of his face and creating an "X". The forces him to tighten his bones and then release them so the lowering process can take place. Taking up Marrow Shift is not an instantaneous feat, instead the post is kept up until he reaches that fifteen percent maximum whilst possibly defending him against enemy attacks in the process. Even though it was/is a very incomplete technique, he was able to deal enough damage to Velour Sasha to force a retreat.

Despite only using the technique for the first time, he was able to channel a few of his techniques through it.

Trivia

 * Though Jane gave him the technique name in a story, it was actually thought of by User:Arukana.