Mydeimos, or Mydei, is a standout character in the Amphoreus storyline who was first introduced in Honkai Star Rail 3.0.

As the crown prince of Castrum Kremnos, Mydeimos abandoned his city after its downfall under Nikador, the Mad King.

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Corrupted by the Black Tide, Nikador waged senseless wars against imaginary enemies, plunging the kingdom into chaos and despair.

Known for his fiery temper, Kremnos’ crown prince is driven by a relentless desire for vengeance. He aims to avenge the people of Castrum Kremnos and reclaim the honor lost to the mad king’s corruption.

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Here’s everything you need to know about this iconic character, including his lore, appearance, and abilities in Honkai Star Rail.

Everything you need to know about Mydei in Honkai Star Rail

Rarity: 5-Star
Path: Destruction
Combat type: Imaginary
Voice actors: TBD (EN), Zhao Chengchen (CN), Azakami Yohei (JP), Ahn Hyo-min (KR)

Mydei in Honkai Star Rail
Credit: HoYoverse

Mydei, one of the Chrysos Heirs and the rightful successor to Castrum Kremnos, plays a pivotal role in Honkai Star Rail’s Amphoreus storyline.

As a Chrysos Heir, he is responsible for defeating corrupted Titans and returning their Coreflame to restore peace to the land. However, his quest is deeply intertwined with his thirst for vengeance.

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Mydei first appears during the mission Silver Chariot, Away to the Blackened Land, where he aids Phainon and their group against the corrupted Furiae Warriors. Here, players get a glimpse of his fiery temperament and relentless hunger for combat.

Yet, his actions reveal a striking contrast: while he is a powerful warrior, he shows little regard for fulfilling the Chrysos Heirs’ prophecy.

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This conflict becomes evident in the mission Night Star, Accompany My Slumber, where he openly declares that Phainon can claim the Demigod title and deliver the final blow to Nikador.

Despite his fiery demeanor, Mydei is bound by his honor. During the same mission, he bets with Phainon on who will kill the most enemies, with the winner entitled to defeat Nikador.

Honkai Star Rail’s Mydei
Credit: HoYoverse

When he loses the wager, he stays true to his word, conceding the victory. Later, upon discovering Nikador’s immortality, he volunteers to stay behind, buying time for the others to escape and devise a new plan with Aglaea.

After Nikador’s eventual defeat, Mydei is released from his battle and witnesses the Mad Titan’s end, thanks to the efforts of Phainon and the Trailblazer.

Although Phainon wants him to grant him the Coreflame, Mydei declines it, remaining steadfast in his earlier decision. His honor and strength shine through during the Coreflame Trial, where he delivers a line that encapsulates his character:

“Kremoans revere strength and might, but that does not mean that we lack etiquette.”

READ MORE: Don’t hurt yourself! How to get unique Amphoreus achievements in Honkai Star Rail