Wuthering Waves: How to Unlock Nightmare Tempest Mephis

Nightmare Tempest Mephis is a powerful Nightmare Echo in *Wuthering Waves* that can serve as an impressive upgrade for main 4-slot Electro characters. Not only does it offer enhanced stats, but it may also improve certain damage rotations compared to its standard version—plus, it boasts a more striking visual effect.

While all Nightmare Echoes deliver similar types of bonuses, most are relatively easy to acquire. Nightmare Tempest Mephis, however, requires completing a few specific prerequisites before it becomes accessible. Below is a detailed guide on how to locate and unlock this formidable boss.

Where to Find Nightmare Tempest Mephis in Wuthering Waves

Nightmare Tempest Mephis resides within the large circular arena located at the Shores of Last Breath, part of the Fagaceae Peninsula. However, you cannot engage this boss immediately upon arrival—you must first fulfill two key requirements.

1. Complete the "Where Winds Return to Celestial Realms" Quest: This exploration quest is set in the Shores of Last Breath and involves combat elements. Although straightforward, it may take some time to complete. Successfully finishing this quest unlocks access to the arena where Nightmare Tempest Mephis appears.
2. Discover All Dream Patrols in the Area: You don’t need to clear each patrol—simply locating them so they appear on your map is sufficient. Once all Dream Patrols have been discovered, a notification will appear indicating that Nightmare Tempest Mephis has appeared and is ready to be challenged.

Should You Use Nightmare Tempest Mephis?

Whether or not Nightmare Tempest Mephis should be used depends largely on your character build and the stats rolled on your Echo. When equipped in the main slot, it grants a passive boost to Electro DMG and comes in either the Void Thunder or Empyrean Anthem Sonata sets. The Void Thunder set benefits general Electro DPS characters, while the Empyrean Anthem Sonata variant works best for characters capable of performing Coordinated Attacks, such as Yinlin and Yuanwu.

Additionally, Nightmare Tempest Mephis features a unique transformation attack different from its regular form, potentially enabling more effective combo rotations depending on your team composition and playstyle. These advantages make Nightmare Echoes worth considering for many builds.

That said, always prioritize Echoes with better base stats and sub-stats over the Nightmare variant. If your Nightmare Tempest Mephis doesn't offer strong rolls, you might achieve better performance using a well-rolled standard Echo instead.