How to beat and catch Calyrex
The first battle against Calyrex is pretty straightforward, as you don't have to worry about lowering his health. This is because you need to reduce his HP to 0 and it will advance the story accordingly.
Calyrex is the very unique type of Psychic / Grass here, so you're just going to want to contribute something to counter either of these. A good Dark or Fire type could easily destroy Calyrex, so bring them in and you shouldn't have too many problems.
There is a lot to do between that and the next fight with Calyrex which will lead to you being able to catch him. You can find it in the guide on Legendary Clue 1, which will walk you through how to get to this point. However, you will end up taking on Calyrex in one of two forms, which will depend on which steed you chose when playing Carrot Seeds.
Plant the carrot seeds in the tomb area and get Shaderoot aura Spectrier carrots as a mount, while placing them in the snow area and getting Glastrier aura ice root carrots as a mount. If Spectrier has been summoned, he will become Psychic / Ghost-type Shadow Rider's Calyrex, while Glastrier's summon will cause him to become Psychic / Ice-type Ice Rider's Calyrex.
Calyrex will ask you to challenge him here and if you can catch him, he will accompany you on your journey. Due to the two type variations, be sure to bring a Pokemon that will help you. The Shadow Rider Calyrex will obviously be 4x weak to Dark and Ghost type moves, while Ice Rider Calyrex doesn't have 4x weaknesses, but has more than 2x available, including Fire, Dark, Steel, Bug, Rock, and Ghost. . . Pick a good Pokemon to go into battle, but also make sure you don't pick one that's too powerful, as you still have to catch them.
Regardless of which one you come up against, they will be at level 80, so choose your Pokemon accordingly. Calyrex will also use Giga Drain, which will restore his health, so be prepared to deal with that when trying to lower his health. Don't let the battle go on too long either, especially if you're up against Shadow Rider Calyrex. For this one in particular, he has an ability known as Grim Neigh, which continues to increase his special attack.
Also, keep in mind that you should always have a Master Ball at your disposal, since Peony gave you one earlier in The Crown Tundra. For those who would rather save this, you can just lower his health and try to catch him the old fashioned way. Definitely make sure to save before the battle, as you always want to be able to reset and try again if you accidentally knock him out.
