Azelf

Azelf is a premier offensive threat in UU due to its elite Speed, high Special Attack, and large movepool. U-turn and Knock Off make it a great offensive pivot that cripples checks like Mandibuzz and Chansey, while coverage moves like Flamethrower, Energy Ball, and Dazzling Gleam allow it to threaten staples like Celesteela, Slowking, and Hydreigon. Meanwhile, Nasty Plot Azelf is a dangerous wallbreaker that threatens specially defensive Pokemon like Chansey, Celesteela, and Assault Vest Tangrowth. It's fast enough to outspeed and KO many other speedy Pokemon like Keldeo and Nihilego, only being naturally outsped by Noivern, Crobat, and the niche Salazzle. Though Azelf is powerful, its frailty means that it has to pivot out or make outright KOs if it wants to last long-term. Common Choice Scarf users like Hydreigon and Diggersby can KO or use U-turn against Azelf, and Azelf is quite vulnerable from priority attacks such as Lycanroc-D's Accelerock and Scizor's Bullet Punch. Azelf's great coverage is limited by its moveslots, as a pivot set will have to often choose between Knock Off for support, Energy Ball to threaten Hippowdon, Swampert, and Primarina, and Dazzling Gleam to better handle Dark-types like Hydreigon and Mandibuzz. Nasty Plot faces a similar conundrum, often choosing between Energy Ball and Dazzling Gleam. Thundurus-T gives Azelf stiff competition as both an offensive pivot and a Nasty Plot sweeper. While Azelf is faster and is better equipped to handle threats like Nihilego, Thundurus-T has a better defensive typing, higher Special Attack, and Electric-type STAB moves for threatening common defensive Pokemon that Azelf struggles to beat like Mandibuzz and Slowking.