What is the name of the character who can glide and climb walls?

The character who can glide and climb walls is Knuckles the Echidna. These abilities distinguish him from Sonic and Tails and let him reach routes and platforms that the other characters cannot access in the same way.

Knuckles glides by jumping and holding the jump button, allowing him to travel horizontally and cling to vertical surfaces. While attached to a wall, he can climb upward or downward. His powerful punches also let him break certain barriers, reinforcing his role as the series' strength-focused character.

Knuckles was introduced in Sonic the Hedgehog 3 in 1994 as a rival who initially guards the Master Emerald and is deceived by Dr. Robotnik. A related mix-up comes from Sonic & Knuckles' lock-on version of Sonic the Hedgehog 2: when played as Knuckles, the original Sonic 2 levels remain intact, but his gliding and climbing change how they can be explored. Knuckles cannot jump as high as Sonic, so some sections become harder.