Greninja

Ash-Greninja

Ash-Greninja remains a prominent offensive Pokemon in the metagame thanks to its great Special Attack, fantastic STAB combination, and high Speed that allows it to outrun even Tapu Koko and Weavile once transformed. Water Shuriken allows it to pick off weakened setup sweepers such as Volcarona and Shift Gear Magearna and faster Pokemon such as Choice Scarf Landorus-T, Choice Scarf Kartana, and Mega Alakazam. Spikes allows it to punish and wear down its checks over time, allowing Ash-Greninja to have an easier time grabbing KOs. However, despite its upsides and ability to match up well against offense, Ash-Greninja struggles against bulkier cores utilizing Pokemon such as Chansey and Toxapex, often just being used to set up Spikes for its teammates. Its fragility also leaves it prone to priority moves such as Mega Medicham and Mega Lopunny's Fake Out, as well as preventing it from pivoting in consistently throughout a battle.

Greninja

Greninja, courtesy of its stellar Speed tier and amazing ability in Protean, is one of the OverUsed metagame's premier offensive threats, as it is more than capable of pressuring both faster, offensively inclined teams and bulkier builds. Its expansive movepool is a major contributing factor to its potency as an offensive force as well: because it has such a high number of move options, it can circumvent would-be counters and defensive checks and leave one's opponent guessing at Team Preview. Additionally, Greninja is one of the few viable offensively inclined user of Spikes and Toxic Spikes, which it is a stellar user of. Greninja only truly falls short when it comes to bulk, which renders it incapable of taking even resisted hits repeatedly, and the inability to run every coverage move on one set.