Great Nailsage Sly

Phase 1

 * Cartwheel Slash: Sly will slash forward with his nail twice before spinning his nail around his body vertically and jumping high in the air. He is briefly vulnerable after landing back on the ground. Sly will not do the spinning portion of the attack if the Knight is too far away.
 * Nail Slam: Sly will jump into the air and slam his nail into the ground. Upon landing, he will swing his nail in an arc above his head. He is briefly vulnerable after the swing. Sly will not do the swinging portion of the attack if the Knight is too far away.
 * Great Slash: Sly will stand in place and charge the Great Slash nail art, telegraphed by white particles floating towards him. When released, the slash's range can potentially hit the Knight even if he is behind Sly. He is briefly vulnerable after the slash. This attack does two masks of damage.
 * Dash Slash: Sly will rush forward and perform the Dash Slash nail art. Sly's dash covers nearly the entire arena, but the slash itself will only occur around Sly at the end of his dash. The slash has roughly the same range as his Great Slash attack. He is briefly vulnerable after the slash.
 * Cyclone Slash: While he is in the air, Sly may occasionally perform the Cyclone Slash nail art. He will freeze in place and white particles will float towards him. During the attack, Sly will fall slowly to the ground towards the Knight while spinning his nail horizontally around him, before rising back up again. Sly is briefly vulnerable after landing on the ground after the attack.

Phase 2

 * Frenzy: Sly begins dashing quickly between the walls, floor, and ceiling. He will occasionally stop in midair close to the Knight and spin his nail vertically around him like a saw blade, moving a very short distance towards the Knight.

Great Nailsage Sly is the final boss of the Pantheon of the Sage, the third of five pantheons. He is significantly more agile than most of the other bosses in the game and can be a great challenge in terms of melee.

Nail jumping on him during the Cyclone Slash attack is a difficult, but effective way to dodge this attack, however it is recommended for the player to simply keep their distance.

For the Frenzy attack, he is very briefly vulnerable after the spin. It is recommended to dash away when he stops near the player, then walk towards him and hit him once with a nail strike. Repeat this enough times, and the fight will be over.

Trivia

 * In the Nintendo Switch reveal trailer, Sly's arena had a more light yellow background like Paintmaster Sheo and Brothers Oro & Mato, opposed to the more dark background the arena has in the final version.
 * Sly seems to be using the Nailmaster's Glory during the battle, as his Nail Arts only take half of a second to charge, unlike the Nailmasters who take about 2 seconds to charge. Sly himself is also the one who grants the charm in the main game.
 * Sly has surprisingly great skills with his nail, despite it being about x4 times large than his body. This is perhaps done for comedic effect and to emphasize his Nailsage status.