Monado Speed appears as one of Shulk's five usable Monado arts in Super Smash Bros. for Nintendo 3DS/Wii U and Super Smash Bros. Ultimate. It will boosts Shulk's ground speed but will reduce his jumping height as well as his damage output. In Super Smash Bros. for Nintendo 3DS/Wii U it will last 15 seconds and have a cooldown of 10 seconds. In Ultimate, it is more powerful, but will only last 8 seconds for 16 seconds of cooldown. Kirby can also performs Monado Speed by copying Shulk in both games.
The symbol that appears on the Monado when Monado Speed is activated is the kanji "疾", which is the base of the word "疾く" (quickly, swiftly).
The cutscene that introduces Monado Speed clearly shows that Reyn and Sharla were given a speed increase at the same time. However, when used in battle, it will only speed up one character.