Dialga

Dialga stands as a powerful nuke in Ubers thanks to its high offensive stats, strong coverage, solid defensive typing, and natural bulk allowing multiple entry points throughout a game and letting it soft check foes like Zekrom and Eternatus. Despite its power, though, it faces stiff competition for a team slot with Eternatus thanks to its fast Speed tier, access to Recover, and strong, no-drawback STAB Dynamax Cannon. Additionally, Dialga's power does not prevent it from having defensive answers; Blissey and Lunala can switch into its attacks and heal off the damage multiple times a game, and Dialga is reliant on proper prediction to bypass other checks, which makes it hard to use. Opposing offense is also a tough matchup due to Dialga's prediction-reliant nature, as making the wrong call can leave it wide open to setup from threats like Zekrom and Xerneas.