Knuckles the Echidna (Sonic Boom)

Knuckles the Echidna is one of the main characters in the Sonic Boom series. He is an anthropomorphic echidna from Angel Island and serves as the muscle of Team Sonic.

Personality
Knuckles is described as a "punch-first-and-keep-punching-until-you-need-a-punch-break" kind of echidna, and the best solution to a problem for him is to smash it to pieces. He is determined and strong of character, but tends to be rather cocky and get into trouble.

Additionally, Knuckles has a huge ego: he clearly think that he is his team's leader and most capable member, and fancies himself very heroic, the latter of which is not entirely without reason though he can exaggerate his own recollection of his accomplishments.

Knuckles is the opposite of Sonic: he is stubborn, likes to take his time and very naive.

He is also not exactly intelligent, admitting himself that he is "as dumb as a rock," and is a little slow on the uptake, particularly when it comes to elaborate plans and math problems as even simplified explanations takes him a long time to process.

He is also a bit goofy at times and easily distracted to the point where he is drawn to things as simple as shiny objects.

Despite his tough personality though, Knuckles is a softy on the inside with some noticeable preferences in particular: he loves nature and is very loyal to his friends.

Knuckles comes off as a little sensitive about his intelligence. While he accepts he is not the smartest, he takes great offense when being called stupid and will go to extreme lengths to prove otherwise. Also, when Knuckles got his team into trouble with a half-baked plan, he sunk into a depression of self-berating over his imposed stupidity (even crying about it) until his friends restored his confidence.