Umbra (陰固/Inko lit: "solid shadow") is a shinki technique that renders the target invisible. It has been shown to work on humans and shinki. To cast it, the user forms a halberd with their fingers and points toward the target.
- Kazuma used it to hide Hiyori from Bishamonten and Kuraha.
- Kazuma used it on himself and Kuraha to get past Kagutsuchi.