Honkai: Star Rail Version 4.3 Launches June 1, Teases New Fate/stay night [Unlimited Blade Works] Collaboration

Honkai: Star Rail has officially revealed Version 4.3, The Lethe Below the Living, set to launch on June 1. The update will continue the ongoing Planarcadia storyline while introducing the playable debut of Mortenax Blade and teasing a brand-new collaboration with Fate/stay night [Unlimited Blade Works] later this summer.

According to HoYoverse, the new chapter will focus on the Trailblazer and Blade separately venturing deeper into the “World in Canvas” as they confront the influence of Lord Ravager Asat Pramad and the seal of the Aeon Voracity.

The update also expands the lore surrounding Planarcadia through the debut of Graphia, the “Mother of Imagenesis,” a millennia-old figure related to the Murata family and the origins of the “Weathering Curse.” HoYoverse says the character will provide new insight into the Graphia family, Phantasmoon Games, and mysteries connected to Himeko.

Version 4.3’s main playable addition is Mortenax Blade, a new 5-star Fire Nihility character. The Stellaron Hunter enters combat by deploying a special Bounded Field through his Ultimate, increasing enemy damage taken while unlocking enhanced abilities and follow-up attacks triggered through ally actions.

The update will also feature reruns for Yao Guang during the first-half banners, while Cyrene and Phainon return in Phase 2. Players who obtain Mortenax Blade through Warps can additionally claim the free “Karmic Fire of the Distant Shore” Trailblaze Outfit piece during the “Gift of Tempered Blade” event.

One of the biggest announcements from the reveal, however, was confirmation that Honkai: Star Rail will once again collaborate with Fate/stay night [Unlimited Blade Works] in Summer 2026. HoYoverse confirmed that Gilgamesh and Archer will appear as collaboration characters, with players able to obtain one of them for free simply by logging into the game during the event period.

The crossover follows Honkai: Star Rail’s previous Fate/stay night [Unlimited Blade Works] collaboration during Version 3.4 in 2025, which introduced Saber and Archer as playable characters.

Outside of the main story, Version 4.3 will also add the “Wispae Amusement Park” event inside the World in Canvas, where players will act as the park’s “Chief Planner,” organizing attractions and visitor routes to attract wispae visitors to themed zones.

A new “Starward Mode” is also being added to Memory of Chaos, Pure Fiction, and Apocalyptic Shadow. The mode requires players to build three separate teams across three stages, rewarding additional Stellar Jades for full completion.

HoYoverse further announced an upcoming collaboration with UGREEN, featuring themed merchandise and events across multiple regions.

Source: Press Release
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