Ragnarök (ラグナロク - Ragunaroku) is Yomi's Ultimate Secret Ninja Art from Senran Kagura: Shinovi Versus. It requires five bars of Ninja Art Energy to use and for Yomi to be at critical health. Yomi becomes able to use it after completing Chapter 4 Mission 01.
Yomi causes her sword to become even larger and starts to spin around, generating a large tornado that carries her up into the air. She then points her sword downwards, and jams it down into the ground, using the air pressure from the wind to enhance the power of the impact a great deal.
The name "Ragnarök" comes from the series of events in Norse mythology.