Two sides of the same blade. Read Shinobi Undercover, Ch. 97 in Shonen Jump for free! https://www.viz.com/shonenjump/chapters/shinobi-undercover?wpcn=CAR_ShinobiUndercover-Simulpub-MSJ399_vizwebsite&wpcrn=ShinobiUndercoverCh97-S-Panel&wpsrc=twitter