Knuckles is ranked 6th, at the bottom of S tier. Knuckles is extremely strong, as best exemplified by his down attack, which can easily KO other characters despite lacking the typical insta-kill behavior. His other moves also deal great damage and knockback as well. Despite his strength, he also has a surprisingly fast speed on the ground and in the air.
However, Knuckles has some overall terrible, almost Blade-level instant kill attacks due to his very short range outside of his rock throw. Said range problems give Knuckles a hard time dealing with swordsmen. His Rock Throw has a slow startup, limited range, and cannot be used in the air, making it an unviable option when fighting projectile-heavy characters. This means that Knuckles must be very careful with his spacing in order to avoid a disadvantageous situation.
Despite his problems, Knuckles is a brilliant character, which puts him near the top.
Knuckles pulls out a huge rock from the ground and immediately throw it in front of him; the rock deals damage as soon as it is pulled out from the ground even at the moment Knuckles has not throw it yet. This is one of the few attacks that cannot be used in succession by holding by the attack button, it requires the player to constantly press it in order to spam the attack, otherwise Knuckles performs his standard attack. It is tied with Mr. Incredible's down attack for the single most powerful attack in the game, dealing 10% damage per frame.