End Shuriken

The End Shuriken (終わりの手裏剣) is an extremely powerful shuriken possessed by the Last Ninja, Yoshitaka Igasaki, capable of destroying the world.

It is first mentioned by Kyuemon Izayoi when she confronts Yoshitaka. During his battle with Gengetsu Kibaoni, he supposedly had the power to permanently seal him with the End Shuriken, but instead used the 48 Sealing Shuriken to imprison him temporarily before he would revive years later. Kyuemon demands Yoshitaka hands over the End Shuriken, while he initially refuses to acknowledge he has such a thing. During their fight, Kyuemon deduces that he couldn't seal Kibaoni permanently because he wasn't strong enough to use the End Shuriken, only for Yoshitaka to tell her that he chose not to.

With the creation of Nekomata, a Youkai that could time travel, Kyuemon sends him ten years in the past to retrieve the End Shuriken. To that end, Nekomata attacks any ninja he comes across, leading him to be confronted by Sasuke/NinjaRed and Yousuke Shiina/HurricaneRed. They are aided by a AkaNinger, who followed Nekomata to the past only to be seemingly killed by Nekomata before the Youkai returns to the present with the End Shuriken. Unbeknownst to Sasuke and Yousuke, AkaNinger had mastered the former's duplication technique, with his copy taking the hit as he followed Nekomata to the present, with what the Youkai believed to be the End Shuriken he was carrying actually being Sasuke's personal shuriken. Later on, after reviving again and again after being destroyed several times in 2015, Nekomata returned to 2005 to try and acquire the End Shuriken again, directed by Izayoi that it should be at the old Igasaki Ninjutsu Dojo. He is unable to find it, however, and is lured into gathering fear as an alternative by the present Takaharu and Fuuka with help from their childhood selves. Once the other Ninningers unite with them, the team of five chase Nekomata back to the present where they destroy him permanently.

Having recently arrived in Japan from America, the sixth Ninninger, StarNinger, starts attacking Youkai in search of the End Shuriken. Tossing the purified Sealing Shuriken of a Youkai aside after his initial effort proves fruitless, StarNinger moves on as the Ninningers discover from that someone else is fighting Youkai. Later on, both the Ninningers and Kyuemon learn that what appears to be the End Shuriken is an accessory on a dress designed by Yoshitaka's daughter and AoNinger's mother, Harukaze Katou, who took it from the house a while back believing it was a mere piece of jewellery. Kyuemon sends Youkai Ittan-momen to capture it, but the Ninningers acquire it through their Ninpou. However, in attempt by Kyuemon to take the "End Shuriken" from AkaNinger by force, it breaks in half, revealing the shuriken to be a fake. As Kasumi produces the dummy End Shuriken which she prepared but hadn't yet swapped. It is realised by both parties, with StarNinger witnessing the events from a distance, that the shuriken was a fake all along and that the real End Shuriken is somewhere else, with Kyuemon vowing to take it first.