This video will go over how to find the Second of three different Nail Arts: The Dash Slash.

Hollow Knight has three different Nail Arts that can be unlocked. Secret Abilities, All 10 Hollow knight abilities location on map Since there were problems in Colosseum at release, you can check rest of bosses as Radiant variant on my channel

All Bosses from Hollow Knight defeated without taking any damage, using nail arts, magic and movement abilities (exception is Radiance where you can't avoid damage without shadow dash).