Oddly, the Dark Dagger uses a polarity for its stance slot, which means it will receive less mod capacity from both Pointed Wind () and Homing Fang (), the only two stance mods for daggers. It is recommended that the stance slot be repolarized into the desired polarity if one wishes to keep using the Dark Dagger for optimal modding.
When equipped without a Stance mod, the Dark Dagger adds a 4th lunging stab on its normal attack combo that propels the Warframe a good distance forward, which is useful for catching up to moving enemies. It also has a 100% chance of inflicting Slash bleed proc, despite the fact that the Dark Dagger has no physical damage element. This effect is lost if one uses the Pointed Wind stance, which replaces the lunge with a sweeping slash.
If the lunge lands behind an unalerted enemy, a stealth attack will be performed instead.
The Dark Dagger and its longer counterpart the Dark Sword were previously physical damage weapons. Update 13.0 changed them to deal purely Radiation damage on their normal attacks, making them the first melee weapons to do so.