Tactician's Mark

Wondrous item, Uncommon, Requires attunement
This tattoo's appearance is chosen by the wearer, but it is always positioned near one or both of their eyes.
Tattoo Attunement. Attuning this item magically turns the needle into a tattoo where you choose. When you unattune, it becomes a needle again.
Tactical DC Bonus. When you force a target to make a saving throw using a feature that is not magical, psionic, or ki-based, the DC is increased by 1.
Tactical Die Upgrade. When you use at least one feature that is not magical, psionic, or ki-based that adds a damage die to one of your attacks, upgrade one of the added dice by one level (d4 → d6 → d8 → d10 → d12 → d20).