Fan Casting Big Sibling Mentor in Sort by Tropes

This character is the hero's good friend. Additionally, the character, being older (though mental age matters more than physical age) and wiser than the hero, also acts as a mentor to the hero in times of need or advice. However, just because the Big Brother Mentor cares about the hero doesn't mean that he won't rebuke him if he gets out of line, and he would even go as far to deal with him physically. He only wants the best out of the hero, but won't hesitate to educate him the hard way if the hero shows reluctance to learn or has a tendency to run headlong into danger. In essence, he's the ideal big brother figure who knows when to get friendly or strict.