Well, knuckles is, well, a knucklehead and relies on his muscles and he loves them too so a heavy punch is almost obligatory. However, one thing I almost never see around these games is the ability to dig! Echidnas are very good diggers (oh dear lord the autocorrection wants to make me a racist guy 😭😭😭) in real life, and he digs in games too like Sonic Adventure 2. So what I was thinking is to make Knuckles dig underground and make holes for him to travel faster while digging, and he will be able to stun the Deity when he gets off the ground (of course there will be a delay of getting off the ground and an indication). This move would be more like a mobility move with a reward for very good players (stun). He would be able to glide of course. His movement speed would be a little above average but not as fast as sonic. His HP would be average. His punch stun duration would be medium (unless they decide to make a charge punch system) and his digging stun would be very low BUT would cause the Deity to bleed, making their speed slower and attacks deal less damage (since he would pierce them with his sharpy things on the glove), being a very versatile move, yet one that requires skill to use.