Knuckles was the guardian of the master emerald, he didn’t let Sonic too close so he wouldn’t cause any harm. Knuckles had a serious aura and dementor although he cares and just a silly guy underneath

Knuckles has his arms crossed as he made sure nobody took or nobody touched the master emerald. Thats when knuckles noticed Sonic reaching for the master emerald to try to touch it. Knuckles then slapped his hand away

Knuckles:”Hedgehog! Don’t you dare even let a finger that emerald!!!”