Zamasu creates a purple, sharp energy blade around his right hand, which is powerful enough to bifurcate a much bigger being, such as a Babarian, in half. It can also be used as a medium to fire Ki Blasts. It can also be used as a defensive move as shown when Future Zamasu used it to block Super Saiyan Blue Goku's punch
Zamasu first attempts to use this technique on Goku after losing to him in their sparring match when Goku stretches out his hand to help Zamasu get up but is stopped by Gowasu. He then used the attack on Planet Babari to kill a Babarian attacking him and Gowasu, despite Gowasu telling him not to. Zamasu also used this attack to threaten Zuno, demanding to know from him information about the Super Dragon Balls and Goku. Later, Zamasu attempts to kill Gowasu and later Goku using the attack but is easily stopped by Beerus. Zamasu, who later would become Goku Black, used this attack to kill Gowasu while he was eating and drinking his tea. Future Zamasu used this attack several times during his battle with Goku and Future Trunks in the alternate timeline.
Goku Black uses a stronger variation of the technique in his Super Saiyan Rosé form. In this form, the blade is much longer. It was first used in his fight against Vegeta, piercing his chest and defeating him instantly. Then uses it again against Goku and Future Trunks. The Enhanced Version has three forms, the first one, which he used to mortally wound Vegeta and then Goku is a long blade resembling a broadsword. The second version is much larger resembling a large cutlass. This version can extend into javelins which he uses to defeat Goku.