Can You Change Shards of Evil in Diablo 4 yes: Prime Evil alignment can be changed through the largest Waking Nightmares, while socketable Soul Splinters can be swapped like seasonal gems.
Season of Hell’s Legacy has two similarly named Splinter systems, so the useful answer starts by keeping Prime Evil alignment separate from the Soul Splinters socketed into Jewelry. Blizzard confirms that the seasonal gems carry both a boon and a liability, while the Prime Evil path controls reputation and activity modifiers.

Can You Change Shards of Evil in Diablo 4 after choosing one?
Since Patch 3.2.4, you can carry up to 99 matching Prime Evil Splinters per stack. That doesn’t give you three active Prime Evil powers at once. You still use the largest Waking Nightmares to get another Splinter and change your active seasonal path.
Yes. Blizzard explicitly says the Prime Evil choice is not permanent. After the seasonal quest introduces the major Waking Nightmares, the largest versions can provide another Prime Evil Splinter so you can move to a different reputation track and reward path.
That is separate from the socketable Soul Splinters used in Jewelry. Those are gear choices rather than one seasonal allegiance, so they can be changed as you change the socketed setup.
How to change your Prime Evil path
Complete the seasonal story far enough to encounter the large Waking Nightmares. After the introductory quest versions, those Capstone-style encounters become replayable on Torment difficulty. Blizzard identifies the largest Waking Nightmares as the place to acquire another Prime Evil Splinter when you want a different path.
The three paths modify different activities: Terror covers Helltide and Infernal Hordes, Destruction covers Undercity and Lair Bosses, and Hatred covers The Pit and Nightmare Dungeons. All three can modify Whispers.
When changing is worth it
Switch when your endgame routine changes. A character that spent early Season 15 living in Helltide may value Terror first, then move into Hatred once Pit and Nightmare Dungeon progression becomes the focus. Boss farmers can instead favour Destruction.
That makes Can You Change Shards of Evil in Diablo 4 an important planning question, because you do not need to treat the first choice as a permanent account mistake.
Changing Soul Splinters is different
The eight socketable Soul Splinters are associated with Andariel, Azmodan, Belial, the Black Soulstone, Duriel, Lilith, Na-Krul and Skarn. Up to three can be equipped among available Jewelry slots. Each brings a boon and liability, and duplicates can be upgraded through Horadric Cube Amalgamation.
Those gear pieces should be swapped whenever the build or activity demands it. A farming combination with Lies, for example, can make sense for easy material runs but be poor for difficult pinnacle content.
Why the terminology causes confusion
Can You Change Shards of Evil in Diablo 4 is easier to understand once Prime Evil Splinters and socketable Soul Splinters are separated. Terror, Destruction and Hatred are seasonal progression choices. Anguish, Sin, Lies, Black Soulstone, Pain, Mother, Hellfire and Damnation are the equipable gems. They interact with the same season but use different progression rules.
What carries over between builds
The useful part of Can You Change Shards of Evil in Diablo 4 is that collection work is not wasted when you change builds. Matching Soul Splinter duplicates remain useful for Amalgamation, and a different Prime Evil path can be pursued later through major Waking Nightmares. Keep flexible pieces until the endgame build is settled instead of pruning the stash around one early setup.
Can You Change Shards of Evil in Diablo 4: what to check in-game
For the underlying Season 15 rules behind Can You Change Shards of Evil in Diablo 4, Blizzard’s Season of Hell’s Legacy overview confirms the Prime Evil paths, the three forms of Waking Nightmare, the Torment 10+ pinnacle versions and the Soul Splinter rarity/Amalgamation system. Use the live tooltip on your own shard for its current numerical value, because build balance can change even when the core seasonal rule remains the same.
Can You Change Shards of Evil in Diablo 4 is worth checking again whenever you change activity, difficulty or core build pieces, because Season 15 makes several rewards and liabilities context-dependent rather than universally good.
