Celesteela

Flying

Celesteela's stellar defensive typing, handy resistances, and impressive mixed bulk make it a potent defensive pivot for Flying teams, allowing it to check physical and special threats and soft check Pokemon like Kyurem. Its Steel typing allows it to check Rock- and Ice-type threats such as Terrakion, Tyranitar, Nihilego, and Weavile. It also has quite the colorful movepool, ranging from options such as Leech Seed, Toxic, Flamethrower, Meteor Beam, and Autotomize, letting it run defensive or offensive sets. Even as a defensive wall, Celesteela has offensive potential with Heavy Slam and Flamethrower, letting it beat Pokemon such as Dragonite and Bisharp, which its competitors like Defog Corviknight fail to do. However, Celesteela lacks a reliable recovery move unlike Corviknight, which can also act as a wincon with Bulk Up or provide Defog support. A lack of a reliable recovery move and its over reliance on Leech Seed + Protect on its defensive set can be taken advantage of by setup sweepers like Bisharp, Garchomp, and Aegislash. Additionally, it also makes it unable to recover against Grass-types, making it harder for it to beat certain bulky Grass-types like Amoonguss. It also cannot stomach ridiculously strong wallbreakers like Choice Band Urshifu-R and Choice Specs Aegislash. Celesteela is also easily shut down by stallbreakers like Mew and Mandibuzz.

Steel

Celesteela's Flying type is invaluable for Steel teams to switch into Ground-type attacks from Pokemon like Landorus and Excadrill while also being neutral to Fighting for Pokemon like Buzzwole and Terrakion. It can pair with Heatran and Aegislash to form the fabled triple immunity core—three immunities on top of Steel's Poison immunity—which many types have trouble dealing with. Good bulk along with the combination of Leech Seed, Toxic, and Protect allows Celesteela to wear down and hugely hinder most teams. It beats a majority of opposing walls like Mantine and Gastrodon, wearing them down while being immune to Toxic itself. On the off chance it KOes an opposing Pokemon, Celesteela can take advantage of the increase in Defense from Beast Boost to be an even greater wall. Though Celesteela is the best Flying-type choice for Steel teams overall, it faces competition from Skarmory and Corviknight, which both have reliable recovery and other distinguishing traits. Corviknight is an invaluable defensive pivot, has Defog, and can stall out Stealth Rock with Pressure. Skarmory offers much greater physical bulk to deal with Urshifu-R and Weavile, Pokemon Celesteela might struggle against in the long run, and can set entry hazards. Further, Celesteela's typing leaves it vulnerable to Fire- and Electric-type attacks from Pokemon like Victini and Thundurus-T.