Unlike most Pokémon games, evolution in Pokémon Legends: Arceus is done manually. That is: you need to meet certain requirements and evolve them in your satchel. Scyther is no different.
The method to evolve Scyther depends of the Pokemon you want to end up with. If it’s Scizor, when you need Metal Coat like in previous games. This can be bought in Jubilife Village using Merit Points. However, if you want to get Kleavor, the Bug/Rock Hisui variant, you need to give your Scyther a Black Auguirite. Gravelers will occasionally drop Black Auguirites when beaten. You can also find a couple in Crimson Mirelands using the Treasure Detector.
Scizor is a familiar Pokémon, so let’s talk about the new guy: Kleavor. Kleavor gets a huge boost in Atk when your Scyther evolves into it, so be sure to prioritize raising the effort level of this stat. Then, you can dedicate grit items to its Def or Spd first, depending on how you want to build it.
Despite its Rock typing, which is notorious for having a lot of weaknesses, Kleavor is only vulnerable to three: Water, Rock, and Steel attacks. It’s resilient to Normal and Poison. This Pokémon can gain one of two abilities: Swarm, which increases the power of Bug-type moves, and Sheer Force, which boosts the power of moves that have additional secondary effects (like lowering stats) in exchange for ignoring said effects.
For more help with Pokémon Legends: Arceus, we at Pro Game Guides have you covered.