Pokemon Legends: Arceus revolutionized the mainline Pokemon games after many years of re-skinning the same formula that's been used from the beginning. With more focus being shifted to catching and discovering Pokemon, rather than becoming the best there ever was, many players feel more compelled to complete the Pokedex than ever.
Though there are not any evolutions as rage-inducing as something like Galarian Farfetch’d in Pokemon Sword and Shield, many evolutions in Arceus are time-consuming and require a lot of dedication to a specific Pokemon. From using strong style moves to satchel hunting to breaking rocks until a Pokemon loves you enough, no Pokedex can be completed without going through these difficult evolutions.
10 Eevee Into Espeon, Umbreon, And Sylveon
Eevee’s evolutions can be found as extremely rare spawns in space-time distortions, but it is more than likely players will need to evolve at least a few Eevees on their own. While Jolteon, Leafeon, and Flareon can be evolved with their respective stones, the rest of the Eeveelutions are friendship evolutions. Friendship can be raised by feeding your Eevee, hitting rocks and trees, defeating opposing Pokemon, and making sure Eevee does not faint.
Once your Eevee's friendship level is high enough (which can be checked by talking to an NPC in Jubilife Village), they will be able to evolve. For Espeon, Eevee must evolve in the daytime, and for Umbreon, it must be at night. Sylveon can be obtained through the same friendship method, but Eevee must have a Fairy-type move in their active moveset.
9 Scyther Into Kleavor
Kleavor is the true first boss of the game, and the first time in Pokemon history players actively fight against an opposing Pokemon themselves. Players will have to toss balms at the intimidating bug/rock type Pokemon, but it cannot be captured in this fight. To command their own Kleavor, trainers will have to first obtain a Scyther, which can be found on the western and eastern outskirts of the battle arena.
With their Scyther in hand, trainers will then have to find an item called black augurite, which can be obtained as a rare drop from either fighting or capturing Graveler, or from ore deposits in the Obsidian Fieldlands. Alternatively, trainers can complete the side quest "A Nosepass to Guide the Way," or hope for them to spawn within space-time distortions.
8 Dusclops Into Dusknoir
Though an alpha Dusknoir can be found wandering around Deadwood Haunt in Cobalt Coastlands at night, trainers will have to go through a bit more effort to evolve their own Dusclops into this chilling ghost type. Dusclops can be found relatively easily also floating around the Deadwood Haunt at night, and players should already have one due to the main story progression in the Cobalt Coastlands.
Trainers will need to find an item called a reaper cloth to evolve Dusclops. The reaper cloth can be found within space-time distortions, but the more reliable way to get your hands on one is to track down missing satchels scattered around the map, and cash in your merit points with the Outpost Trader in Jubilife Village. The reaper cloth will cost a hefty 1400 merit points.
7 Magmar Into Magmortar
The signature first-generation volcano Pokemon Magmar's evolution, Magmortar, is one of the most powerful fire types in the Hisui region. With gaudy base special attack stats, it is no surprise it is quite difficult to come by. Magmortar does not spawn in the overworld in Arceus, so players will have to first obtain a Magmar from Firespit Island in the Cobalt Coastlands.
Next, trainers need to obtain a rare item called the Magmarizer. Like Magmortar, this item will not appear naturally in Hisui, as trainers will have to spend a whopping 1400 merit points to purchase it. Or, with some luck, the item will spawn in space-time distortions, or as a special purchase at Ginter's Ginko Guild Shop for 10,000 Pokedollars.
6 Electabuzz Into Electivire
Electivire, the electric equivalent of Magmortar, is an imposing physical attacker with a wide movepool. A powerful alpha Electivire, which can be captured, blocks your way to the peak of Mount Coronet, but if you want to evolve one from scratch, you'll first have to get your hands on an Electabuzz, which can also be found on the snowy peaks of Mount Coronet.
Similar to Magmortar, Electabuzz needs an item called the Electirizer to evolve. This rare item can only be obtained through purchase with the Outpost Trader for 1400 merit points, or a special purchase with Ginter called "Electricity Box" for 10,000 Pokedollars.
5 Sneasel Into Weavile
Sneasler, the new regional evolution of Sneasel, is a ridable Pokemon you will be able to access once making it to the Coronet Highlands. Though trainers can obtain and evolve the Hisuian Sneasel relatively easily, evolving into Weavile is a different story. The non-regional variant of Sneasel only appears in space-time distortions in the Obsidian Fieldlands.
Once players have their second-generation version of Sneasel, they will have to acquire a razor claw, which can be obtained by defeating or capturing Sneasel (don't worry they can be the Hisuian variant), or for trading in 1000 merit points with the Outpost Trader. Then, once it's nighttime, trainers can use their razor claw on Sneasel for it to evolve into Weavile.
4 Ursaring Into Ursaluna
Ursaluna is another ridable Pokemon in Arceus Legends, obtained in the Crimson Mirelands. Though trainers can use Ursaluna to dig for treasure, they will need to evolve an Ursaring if they want to use Ursaluna in battle. Ursaring can be found in both the Crimson Mirelands and the Coronet Highlands.
Next, players need to acquire a peat block. The peat block is rare but can be obtained by hunting with Ursaluna, breaking ore deposits, purchasing a "Hunk of Coal" from Ginter, or by completing the side quest "Gone Astray...In the Icelands." With the peat block in your satchel, head to the Crimson Mirelands and wait for a full moon; only then will Ursaring be able to evolve into Ursaluna.
3 Basculin Into Basculegion
Basculegion, another ridable Pokemon obtained in the Cobalt Coastlands, again cannot be used in battle unless you obtain the Pokemon for yourself. Basculegion's pre-evolution, Basculin, is a pesky and skittish water type that spawns in the Cobalt Coastlands and Obsidian Fieldlands.
After obtaining Basculin, you will need to use it in battle and accumulate 294 recoil damage by either using wave crash or double edge. This damage does not need to be accomplished in one battle, so be sure to heal as often as possible, as the counter will reset should Basculin faint. Once this recoil damage is achieved, Basculin will be ready to evolve.
2 Quilfish Into Overqwil
Though Overqwil, the cleverly named Hisuian evolution of Quilfish, can be found as an alpha Pokemon as part of the main story. It is a bit more difficult to evolve from scratch. First, you will need to get your hands on a Quilfish, which can be found swimming in both the Obsidian Fieldlands and the Cobalt Coastlands.
Next, Quilfish will need to learn and master the move barb barrage, which is achieved at levels 15 and 25, respectively. Once mastered, Quilfish will need to use barb barrage in strong style 20 times. After this is achieved, Quilfish will be ready to evolve into its dark/poison typing.
1 Stantler Into Wyrdeer
The first ride Pokemon players will receive is also one of the most tedious to evolve. Wyrdeer, the new Hisuian evolution of Stantler, does not appear naturally in the overworld, so you will need to first obtain a Stantler of your own. Though it tends to flee from battle, Stantler can be found relatively easily in the Obsidian Fieldlands.
With Stantler on your team, it will next need to learn and master psyshield bash, which is accomplished at levels 21 and 31, respectively. Next, you will need to use psyshield bash in battle in agile style 20 times. Upon doing so, you will finally have your hands on this powerful and elusive Normal/Psychic-type.