In BTD5, this upgrade increases attack range and attack speed of a Ninja Monkey from one attack every 18 frames to one attack every 15 frames, giving it 20% more attack speed. After upgrading, the ninja turns white with a black bandana.
In BTD6, this upgrade increases attack speed for all of its attacks by 66.7%, thereby increasing the attack speed for the shuriken attacks from every 0.7s to every 0.42s. Upgrading will add a white headband to the Ninja Monkey.
- Ninja Discipline is an extremely cost-efficient early game tower.
- Seeking Shurikens will allow it to use its popping power fully.
- They are usually used to lead into higher tier top path Ninjas.
- Ninja Discipline will also increase the rate of Distraction and Counter-Espionage applying, and will also increase the attack speed of Flash Bomb and Sticky Bomb effects, so it is recommended to crosspath this path for those towers.
In BTD5, the upgrade picture is of a white scroll with illegible writing.
In BTD6, the upgrade picture is a shuriken which appears to be fast moving.