Calyrex

Similar to Kubfu and Urshifu at the Isle of Armor, the Crown Tundra has introduced a new set of legendaries that is not part of an existing group (Regieleki and Regidrago being part of the legendary golems) or a variation of an existing ones (Galarian Articuno, Zapdos, and Moltres). These Pokemon are called Calyrex, Glastrier, and Spectrier. In order to obtain Calyrex and either Glastrier or Spectrier, you will need to follow these steps.

First, go to Peony’s house. There, you will find a stone crown on his table. He will give it to you; then you can take it and put it on the statue in the middle of Freezington. This will trigger a battle with Calyrex, a pure Psychic type with the Unnerve ability. You are unable to catch it at this point. Simply knock it out to continue the story. Calyrex will then possess Peony and ask you to talk with various people around town, namely the mayor, the man next to the garden, the lady with the Spheal, and the two ladies with the Swablu. After speaking with Calyrex again, you will learn that the mayor has left. You can find him at the ruins in the Giant’s Bed, who will tell you about some special carrot seeds. Once you go back to town, you can find a man in the centre of town who will offer you carrot seeds for 8 Dynite Ore. You can then plant those seeds in either the frozen soil at Snowslide Slope, or the haunted soil at the Old Cemetery. Planting them in the former means you will encounter Glastrier, a pure Ice type with an ability called Chilling Neigh, which will raise its attack one stage for every Pokemon it defeats in battle. Planting them in the latter means you will encounter Spectrier, a pure Ghost type with the ability Grim Neigh, which will raise its special attack one stage for every Pokemon it defeats in battle. Regardless of where you decide to plant the seeds, you will be unable to encounter the other. After planting the seed, Calyrex will grow a single Iceroot Carrot or Shadowroot Carrot depending on where it was planted. After that, the horse will run into town, and you will need to battle it. You are also unable to catch this Pokemon, so just knock it out. After doing so, the horse will run away. Speak to Calyrex again and it will grow a petal. Speak to the mayor inside his house and he will create the Reins of Unity. Then, travel to the Crown Shrine, which is up Snowslide Slope and through the tunnel. There, you will place the carrot from earlier, and wait in hiding for it to appear. Once it does, Calyrex with mount the horse, and become one Pokemon. It will have an ability that is a combination of the two Pokemon’s (Unnerve and either Chilling Neigh or Grim Neigh, depending on the horse) and a typing that is a combination of theirs as well (Psychic/Ice if Glastrier or Psychic/Ghost if Spectrier). Here, you can catch it, and get two Pokemon for the price of one. You can either keep the two together, or use the Reins of Unity to separate them into two (similar to Kyurem with Reshiram/Zekrom and the DNA Splicers or Necrozma with Solgaleo/Lunala with the N-Solarizer or N-Lunarizer respectively).