Surprised Pikachu

Arceus finds itself a niche on offensive teams thanks to its access to a consistent and strong priority move in Extreme Speed. The move also helps with picking off faster weakened threats such as Geomancy Xerneas and Rock Polish Primal Groudon and preventing them from netting excessive damage on the team. Thanks to a lack of weaknesses outside of Fighting and solid bulk, Arceus can act as a blanket check for a good portion of unboosted threats in the tier and easily set up late-game to clean up the opposing team. An immunity to Ghost also grants Arceus an opportunity to occasionally switch into the likes of Lunala. Unfortunately, Arceus is strapped for moveslots, and depending on what moveset and coverage moves it opts for, it will be easily stopped by common walls in the tier, such as Zygarde-C, Celesteela, both formes of Giratina, Skarmory, and Ferrothorn. Arceus is also somewhat vulnerable to revenge killing due to its lack of resistances and the prevalence of many faster threats that are resilient or immune to Extreme Speed, such as Mega Salamence, Ultra Necrozma before Ultra Burst, Mega Gengar, and the worst, Marshadow. Due to Arceus's inconsistent performance that is dependent on matchups, it faces stiff competition from Arceus-Ground, which is more consistent with a stronger STAB move.