The Mark of Tarakudo is a magical symbol bearing the face of Tarakudo, King of the Shadowkhan and Lord of All Oni. The mark will appear if one were to attempt to summon the Shadowkhan to do their bidding.
Any human who tattoos this Mark onto their body will gain the ability to summon and control Ninja Khan without wearing an Oni Mask or using a dark spell. However, doing so will gradually turn the person into an evil demon with blue skin, red eyes and fanged teeth, making them resemble a Shadowkhan themselves (while also allowing evil within the tattoo to consume their very being).
The Mark cannot be removed unless a magical potion is used or by a magic spell in sealing Tarakudo and his shadow magic away. Tarakudo himself has a magical link to such symbols — either by a tattoo or through the dark spell in summoning Shadowkhan.
- Queen of the Shadowkhan (Season 2)
- Sheep In, Sheep Out (Season 3)
- The Masks of the Shadowkhan (Season 4)
- Ninja Twilight (Season 4)