This is Roku kanoshi, the 'Golden child' of the Kanoshi family whom failed where Ayami succedded. (it was intentional that the yellow-orange colour chosen for roku was a shade of gold for this well known title)

to keep the name Roku, i made his quirk (superpower) one called 'Hex shield'

with this ability roku can create golden translucent hexagon shaped panels in spherical shapes. When these barriers are present, any entity or object that roku views as an 'enemy' will be launched out of the barrier radius at extreme speeds, while anything not viewed as an enemy can physically pass through the barriers however they please.

When growing up Roku was incredibly intelligent and academically inclined, and with a quirk with protective capabilities such as his, his parents pushed him to become a great hero, and bring fame and fortune to the family, However he failed the entrance exam to UA high school, so he tries again the next year, and fails once more. Depressed from dissapointing his parents he becomes a recluse and shuts himself in his room for very long periods of time. 

After Ayami gets into UA from recommendation of a pro hero, the two grow further appart, as Roku believes his sister who has always been treated worse than him has achieved what he could not. On the other hand Ayami panicked and accepted the recommendation with the intention of upholding her brother's goal, not knowning how it would send him deeper into a spiral.

After a long time appart Roku comes to terms with the current state of his life, and for the first time asks ayami for help, on knew imaginative ways to use his quirk and how to perfom on the same level as the people she is learning from. Eventually with her assistance, roku became a vigilante, still protecting people but not going through the official channels to do so, thus he is frequently on the run from authorities.