Among all of the new Pokémon introduced in Generation IX, there are a handful that have special evolution requirements in Pokémon Scarlet and Violet. There are some that need to be walked 1,000 steps before they'll evolve, while others, like Kingambit, require specific tasks to be completed.
Charcadet, another new Pokémon introduced this generation, also has some version-specific requirements to evolve. You'll have to work to evolve Charcadet, but here's how to get its different evolutions.
How to evolve Charcadet into Armarouge.
Charcadet will only evolve into Armarouge in Pokémon Scarlet, and you'll have to get a specific item in the game to complete the evolution.
Visit the city of Zapicico and speak to the man wearing a pink shirt near the fountains; he'll have a bubble above his head that reads "Fancy a trade?"
In Pokémon Scarlet, you'll want to to trade him 10 Bronzor Fragments to get the Auspicious Armor, which can then be used to evolve Charcadet into Armarouge. You can find Bronzor among ruins around Paldea.
Give the Auspicious Armor to your Charcadet and it will evolve into Armarouge.
If you want Armarouge in Pokémon Violet, you'll have to find a friend to trade you for it, or ask them to get the item necessary for the evolution and give it to a Pokémon that you'll trade. This is the only way to get Armarouge in Violet, as you cannot trade for the Auspicious Armor, even if you're in multiplayer mode with a friend who has Scarlet.
How to evolve Charcadet into Ceruledge.
Just like how Amarouge is only available in Pokémon Scarlet, Ceruledge is only available to Pokémon Violet players. To evolve your Charcadet in Pokémon Violet, you'll also want to visit the same man by the fountain in Zapicico, except he will ask for 10 Sinistea Chips. You can find Sinistea in East Province near Zapicio or near Alfornada.
Once you've traded the 10 Sinistea Chips for the Malicious Armor, you can give it to your Charcadet for it to evolve into Ceruledge.
Again, you cannot obtain this item in Pokémon Scarlet, so you'll have to ask a friend to trade you a Ceruledge or a Pokémon with the Malicious Armor if you want Ceruledge in this version of the game.
Pokémon Scarlet and Violet are now available exclusively for the Nintendo Switch.