ALL CREDIT FOR ORIGINAL SUGGESTION
GOES TO @Hero
Element??: NinjaGOES TO @Hero
Move: SpeedSlash
Type: Damage
Item Required: Flint Sword
Durability Taken: 2 + (dmg / 1.5) uses
Damage: 2 + (0.52 * bps) Damage
Range: Melee
Cooldown: 3.5 seconds
Description: The player must be holding a Flint Sword for this to work. The basis of this ability is that, the faster you run, the more damage you do. This takes advantage of the Ninja's (presumed) higher mobility and speed. The damage of this ability is 2 base damage + (0.52 * Blocks per Second). So if you were traveling at a max sprinting speed of 5.612 bps, the ability would do roughly 5 damage (2.5 Hearts), the damage being higher the faster you travel, with Speed 2 being 6 damage (3 Hearts). This comes a high durability taken from the sword, with the higher damage you do, more durability is taken off. The durability and damage will always round up.
Thanks for reading and make sure to leave criticism!