In sixth place we have Calyrex, but there are three forms of Calyrex, and the base form I just showed you is definately not on this list. The one on this list is Calyrex Shadow Rider.
Calyrex Shadow Rider is the #6 placed Pokémon, and it is the final AG ranked Pokémon left to appear on this list (other than Arceus). This Pokémon is just plain broken in the current format, and there is many reasons why.
Calyrex has one of the best special attack stats ever today, expecially in the Scarlet and Violet. It has pretty good bulk, but could be better for a legendary, and it has an insane 150 base speed. That base speed outspeeds every other Pokémon on the list. Its attack doesn't matter and along with this insane collection of stats for an all out attacker, this has an insane moveset to match.
Calyrex Shadow Rider is a special attacking beast as you just saw with its stats, but that is not the whole story.
Astral Barrage is a 120 base power move that can hit both targets, with NO DRAWBACKS. Psychic and Psyshock are both special psychic type moves, but Psyshock calculates from the physical defense of the opponent. Grass Knot deals more damage the heavier the opponenet is and is a good coverage move. Lastly, Nasty Plot boosts your special attack by two stages. Great moveset for a special attacker since it can also deal with special walls with Psyshock. And if you thought that was enough, I have something to tell you.
Calyrex Shadow Rider is a fusion between Calyrex and Spectrier, which both have different abilities that make sense lore wise. This fusion is just Calyrex riding Spectrier so both abilities would make sense on it, so how do you handle this. According to Game Freak, give it both.
Calyrex Shadow Rider has the ability As One (Shadow) When Calyrex is in Shadow Rider or Ice Rider, it get either As One (Shadow) or As One (Ice). They both give the Pokémon two separate abilities, one being Unnerve, and the other being either Chilling Neigh or Grim Neigh. Chilling Neigh is just Moxie, which raises attack on every KO, and Grim Neigh, the ability on Shadow Rider, is just special attack Moxie. So what you do is just double your special attack turn one and raise it every KO after that. This is an unstoppable beast except for Pokémon holding the choice scarf.
Even though this creature looks overpowered, in my opinion, it always doesn't do everything you want to do. Just under enough damage, just under enough bulk, just under enough speed. That last one is a lie, except for the fact that unless Calyrex has a choice scarf or the move Tailwind has been set up, it has a major weakness to choice scarf and booster energy speed. And it just has not enough bulk to survive these hits. If you can get the Nasty Plot off and there is no one outspeeds you, you basically win however.
They should have nerfed this. This was manageable in Generation 8 since the power level was so high, but in Generation 9 where there is a lower power level due to the Zacian nerf and removal of megas/primals and Dexit for Pokémon like Xerneas, this thing can truly dominate. The Pokémon has proved itself, and that is unfortunate for all six of these.