In Xenoblade Chronicles 2, it is shulk's level 3 Blade Special and can deal damages that bypass guards. At level 1 it has 60% chances of bypassing guards but once the related section of Shulk's Affinity Chart, it will bypass guards each time. Malos also uses it in his later boss battles.
Super Smash Bros. series
Unlike in the Xenoblade series where Monado buster is an attack, in the Super Smash Bros. series, it acts more like a buff.
Super Smash Bros. for Nintendo 3DS/Wii U
Monado Buster is introduced in Super Smash Bros. for Nintendo 3DS/Wii U as one of the five selectable options available when activating Monado Arts. Buster boosts Shulk's damage and lower his KO power and defense for 15 seconds and can be used after a 10 seconds cooldown.
Super Smash Bros. Ultimate
Monado Buster's damage output and damage recieved is boosted in Super Smash Bros. Ultimate but in turn, the duration of the buff was lowered to 10 seconds and now has a 14 seconds cooldown.