What's Coming in Honkai Star Rail 4.3 — Full Breakdown

Honkai: Star Rail Version 4.3 "The Lethe Below the Living" was fully revealed during the Special Program on May 22, 2026 — and the stream delivered one of the most significant update reveals in the game's history. Mortenax Blade, a brand new endgame mode requiring three teams, two new Relic sets, and the return of Fate/stay night in the biggest collab announcement yet. Here's everything confirmed.

🔥 Mortenax Blade — The New 5-Star Nihility Character

Mortenax Blade is the headlining character of Version 4.3 Phase 1 and the first major Blade variant released since the original. He is a 5-star Fire element character following the Path of Nihility — a combination that positions him as a damage-amplifying debuffer who makes the entire team hit harder while dealing meaningful personal damage.

His kit centers on vulnerability debuffing: Mortenax Blade reduces enemy DEF, and his signature Relic set — the Smith Set — is built entirely around capitalizing on that debuff. The Smith Set 4-piece bonus grants the wearer 28% increased Critical Damage against DEF-reduced enemies and gives the entire party a 15% damage bonus for two turns every time a DEF reduction is applied. In a team built around Mortenax Blade's debuffs, that 15% party buff triggers consistently throughout every rotation.

Pulling Mortenax Blade during Version 4.3 also unlocks an exclusive Trailblaze Outfit: "Karmic Fire of the Distant Shore." This outfit is tied specifically to the 4.3 version window — it will not be available after the version ends. If you're planning to pull him, pulling during 4.3 is the only window to secure this cosmetic.

Version 4.3 launches on June 2, 2026. Mortenax Blade's Phase 1 banner runs from the version launch through the Phase 1 end date.

💎 New Relic Sets — Smith and Navigator

Version 4.3 introduces two new Relic sets that are immediately relevant to the current endgame meta.

Smith Set is Mortenax Blade's best-in-slot set and one of the strongest team-support Relic sets released in recent versions. The 2-piece bonus grants 12% Max HP — a minor defensive stat. The real value is the 4-piece: the wearer deals 28% increased Crit Damage to enemies with DEF reduction applied, and inflicting DEF reduction on any enemy grants the entire party a 15% damage bonus for two turns. In a Mortenax Blade team where DEF reduction is a constant, this 15% party buff maintains near-permanent uptime.

Navigator Set is the offensive alternative for characters who cycle their Ultimate frequently. The 2-piece grants 12% ATK. The 4-piece increases Ultimate damage by 18% for two turns after the wearer uses their Ultimate, stacking up to three times for a theoretical maximum of 54% Ultimate damage bonus if you can stack all three. This set rewards high Ult-frequency characters and will likely see strong use on units built around Ultimate-centric rotations.

⚔️ Starward Mode — The Most Controversial Addition Yet

The biggest gameplay change in Version 4.3 is also its most divisive: Starward Mode. Starting in 4.3, Memory of Chaos, Pure Fiction, and Apocalyptic Shadow will each receive a new high-difficulty "third wave" added to their existing rotation.

The fundamental change is this: where endgame content previously required two functioning teams, Starward Mode requires three. Each of the three base endgame modes will have a Starward tier that needs a full third team composition to clear. The 100 Stellar Jade reward attached to Starward completion makes it a non-optional goal for players who want to maximize their pull resources each cycle.

The community reaction has been sharply split. Players who have invested in deep roster breadth see this as a meaningful new challenge that rewards their investment. Players who already felt stretched maintaining two strong teams are less enthusiastic about a system that effectively increases the minimum investment required to stay competitive in endgame rewards. HoYoverse has not indicated any plans to adjust the structure before 4.3 launches.

The practical implication: Trailblazers who have been playing casually with one or two focused teams should start building out their roster depth now, before June 2. The gap between the first two waves and Starward Mode is designed to be meaningful.

⚙️ Version 4.3 Story — The Lethe Below the Living

Version 4.3 closes the Planarcadia arc that has been the central story setting since Version 4.0. "The Lethe Below the Living" — Lethe being the river of forgetfulness in Greek mythology — signals a story beat centered on memory, loss, and what lies beneath the dream-like reality of Planarcadia. The full story details will be available at launch, but the version title suggests the narrative goes deeper into Planarcadia's true nature before moving on to the game's next destination.

⭐ Don't Miss — Fate/stay night Collab Part 2

The stream's biggest surprise wasn't Mortenax Blade — it was the official confirmation of Fate/stay night [Unlimited Blade Works] Collaboration Part 2, titled "Imagenae Holy Grail War." Full details in the dedicated collab article, but the headline: Rin Tohsaka, Gilgamesh, and Archer are all coming on July 24, 2026, and every Trailblazer gets one of them for free. This is one of the most generous free-character offers in the game's collab history.

📅 Version 4.3 Checklist — What to Do Before June 2

• Claim your Evanescia banner pulls before Phase 2 ends — the 4.2 Phase 2 banner closes when 4.3 launches. Evanescia reruns are not guaranteed quickly.
• Clear all current Simulated Universe weekly missions — progress resets with the version update. Don't leave Stellar Jade on the table.
• Build a third team now — Starward Mode requires three teams from day one of 4.3. Use the remaining 4.2 time to identify which characters form a viable third composition from your roster.
• Farm Smith Set materials in advance — once you know which domain drops the Smith Set, prep your Trailblaze Power budget to start farming immediately at launch.
• Save for Fate collab (July 24) — Rin Tohsaka, Gilgamesh, and Archer all arrive in what will be 4.4 or 4.5. If any of them are priorities for you, begin saving Stellar Jade now rather than spending on rerun banners in 4.3.

🛒 Enter Version 4.3 Ready

Version 4.3 raises the endgame bar with Starward Mode, introduces one of the game's most support-forward Nihility characters, and sets up what will be the biggest collab of 2026. Trailblazers who want to hit the ground running on June 2 can explore trusted Honkai: Star Rail Accounts to enter 4.3 fully resourced, maximize every event and Relic farming session with expert Honkai: Star Rail Hourly Services, or clear every Starward Mode tier effortlessly through reliable Honkai: Star Rail Boosting.

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