Doublade
Attack
Defense
Stamina
Best Movesets
Shadow Claw is the ideal Fast Move for Doublade, sporting high power with STAB and great energy generation, as well as strong neutral coverage.
Backing this up is Sacred Sword, which grants Doublade nearly perfect coverage alongside Shadow Claw, as well as an incredibly powerful tool in PvP that allows it to throw out frequent and dangerous attacks. Finally, Gyro Ball is... something. It's a bit weak, but it adds coverage and can help deal with things that resist Fighting.
With an outstanding typing, a strong moveset, and a solid stat-spread, Doublade hits the Great League as a spammy and powerful threat that can tear down the opposition with a mix of good Fast and Charged Moves, the latter of which come out blindingly fast and frequently. It has many strong wins against meta Pokemon, but it also has issues with others, making it a bit of a mixed-bag that needs the right team to succeed. While it has good matchups against many Pokemon that could be considered a bit more neutral on the surface, it can also end up trapped in a losing matchup relatively easily, leaving a MASSIVE hole in the team thanks to Doublade's high generalist performance.
Then there's the monster in the room: Aegislash. Why utilize Doublade when Aegislash is right there? Well, to start with; Doublade has stronger Fast Move pressure thanks to Shadow Claw, making it a bit harder to play around with shields up. It also has access to Sacred Sword, which hits extremely hard and fast with very different coverage. Aegislash wins out in terms of raw power with its destructive Blade forme boosted Shadow Balls that demand shields to deal with in many cases, but Doublade has strong performance itself that definitely makes it worth considering.
