For me, it's Nnoitra and Toshiro. I hated Nnoitra in the anime, I thought he was just a generic asshole villain, but his extra story in RoS made me like him and notice his depth. Also his personality and voice acting during gameplay is goated. Toshiro is way cooler in the game with his powers unlike in the original anime.
Anything to be less niche I guess
No ascending and transforming into an Otsutsuki by consuming a Thorn Bulb? No glow up, or getting his arm back, and finally be an Otautsuki like he always wanted to? His only solution to killing Boruto was trying to sneak attack him, and now it's kidnapping Sarada to lure Boruto to Jura and Hidari. Because if this is really all his role in this arc, and die at the end or something, then it's one of the most wasted characters I have ever seen in my life.
He didn't even lead Inazuma Break, Haru did. Worst Raimon captain ever.