Sekiro's Katana Sword – Undead Cut Katana – Sekiro Shadows Die Twice Replica Katana – Red Blade

Strictly speaking, there is no "best" removable or farmable katana in Sekiro: Shadows Die Twice because Wolf uses only one primary melee blade: the Kusabimaru. Unlike traditional Action-RPGs like Dark Souls or Elden Ring, Sekiro does not feature lootable swords with varying attack statistics, scaling rates, or weapon tiers. The Kusabimaru is permanently locked as Wolf's main weapon. Therefore, the strongest primary katana in the game is simply the Kusabimaru, whose combat effectiveness relies entirely on player mastery of the Parry/Posture system rather than numerical weapon upgrades.

Understanding the Combat Design: Fixed Weapon vs. Player Skill

Developer FromSoftware deliberately built Sekiro: Shadows Die Twice around an action-focused combat framework rather than an RPG gear-progression model:

• The Single-Blade System: The Kusabimaru—a heritage katana gifted to Wolf by his master, Kuro the Divine Heir—occupies the primary weapon slot permanently. Players cannot loot, purchase, or craft alternative primary swords from bosses or vendors.
• Absence of Weapon Stats: The Kusabimaru does not possess traditional RPG parameters such as base attack power, elemental affinities, or physical durability. Offense increases globally across Wolf's character profile by defeating major bosses and consuming Battle Memories at Sculptor's Idols, which raises raw Attack Power across all sword strikes universally.
• Posture over Health Bar Depletion: Combat superiority in Sekiro is governed by the Posture system (Taikyoku). The "best" combat performance is achieved not by equipping a higher-tier sword, but by landing Perfect Deflects (Parries) to build enemy Posture meters until an instant-kill Deathblow opportunity opens.

The Role of the Mortal Blade: Secondary Tool, Not a Replacement

A common point of confusion among players searching for the "best katana" involves the Mortal Blade (Fushigiri), a legendary crimson blade acquired at Senpou Temple:

• Combat Art Integration: Obtaining the Red Mortal Blade does not replace the Kusabimaru as Wolf's primary light/heavy attack weapon. Instead, it serves as a specialized secondary weapon utilized exclusively for specific Combat Arts (such as Mortal Draw and Empowered Mortal Draw).
• Consumable Spirit Emblem Usage: Executing strikes with the Mortal Blade consumes Spirit Emblems. While it deals massive chip damage through enemy guards and permanently slays immortal bosses (such as the Guardian Ape and Corrupted Monk), players cannot execute standard light attacks, deflects, or counter-strikes using the Mortal Blade alone.
• The Dual-Wield Distinction: In combat animations, Wolf draws the Mortal Blade from his back only during the activation of its specific technique, immediately returning it to its scabbard while retaining the Kusabimaru in his right hand.

Augmenting Combat Efficiency: Prosthetic Tools and Combat Arts

Because players cannot replace the Kusabimaru with a higher-tier katana, optimizing damage output and tactical advantage relies on combining the base blade with complementary systems:

• Shinobi Prosthetic Tools: Equipped on Wolf's left arm, tools like the Loaded Axe (breaks wooden shields), Flame Vent (inflicts Burn status and opens targets to sword strikes), and Loaded Spear (strikes exposed vulnerabilities) serve as Wolf's true "secondary weapon" arsenal.
• Sword-Enhancing Combat Arts: Skills unlocked through Ninja, Ashina, and Temple Skill Trees modify how Wolf strikes with the Kusabimaru. Techniques like Ichimonji: Double (recovers Wolf's own Posture while crushing enemy defenses) or Nightjar Slash (rapidly closes distance) drastically alter the utility of the base katana without changing the physical weapon.
• Ninjutsu Techniques: Equipping Ninjutsu skills—such as Bloodsmoke Ninjutsu or Puppeteer Ninjutsu—allows Wolf to trigger tactical area-of-effect abilities immediately following a successful stealth Deathblow delivered with the Kusabimaru.

Summary Checklist: Weapon Mechanics in Sekiro

• Primary Melee Katana: Kusabimaru (Permanent, irreplaceable primary weapon used for all base attacks and deflections).
• Lootable / Swappable Katanas: None (Enemies do not drop weapons; vendors do not sell alternative swords).
• Secondary Story Katana: Mortal Blade (Functions strictly as a Combat Art tool consuming Spirit Emblems, not a primary sword).
• Stat Enhancement Method: Memories / Attack Power (Increasing damage output is tied to boss progression, not weapon upgrades).

Strictly speaking, no, the Mortal Blade is not "better" than the Kusabimaru because they serve fundamentally different functions in Sekiro: Shadows Die Twice. The Kusabimaru is Wolf’s permanent primary weapon, responsible for all basic attacks, deflections (Parry), and Posture management without any resource cost. The Mortal Blade (Fushigiri), on the other hand, is a specialized secondary artifact that functions as a high-damage Combat Art and narrative plot device. It deals massive chip damage through enemy guards, but cannot perform standard light attacks, parries, or replace the Kusabimaru as a primary blade.

Functional Comparison: Main Weapon vs. Tactical Skill Tool

Comparing the Mortal Blade directly to the Kusabimaru as a traditional weapon upgrade is a common misconception among players. Their mechanical roles are distinct:

• Resource Cost & Accessibility: Swinging the Kusabimaru costs nothing, making it available 100% of the time for offense and defense. Using the Mortal Blade (via techniques like Mortal Draw or Empowered Mortal Draw) consumes Spirit Emblems (typically 3 Emblems per activation). While it can still be cast when Emblems reach zero, its range and overall damage drop significantly.
• Defensive Capability: The Kusabimaru is the only weapon capable of performing Perfect Deflects—the single most vital mechanic in Sekiro’s combat loop. The Mortal Blade cannot be used to deflect incoming enemy strikes, boss peril attacks, or missile projectiles.
• Guaranteed Guard-Piercing Damage: Where the Mortal Blade excels over standard Kusabimaru slashes is its ability to inflict Vitality and Posture damage through an opponent's block. Even when a boss guards against a Mortal Draw, a significant portion of dark/crimson damage passes directly through their defense.

Narrative Purpose: Normal Combat vs. Immortality Severance

Beyond gameplay statistics, FromSoftware separates these two swords based on absolute lore constraints:

• The Kusabimaru (The Heritage Katana): Gifted by Kuro, the Divine Heir, the Kusabimaru carries the literal ethos of its name ("To bind or restrain"). It represents a shinobi's duty to protect human life without unnecessary slaughter. Mechanically, it defeats mortal enemies and builds Posture until a regular Deathblow can be delivered.
• The Mortal Blade (The Fushigiri): The Crimson Mortal Blade (named Gracious Gift of Tears / Bairai) possesses the unique supernatural property of Immortality Severance (Fushigiri). Regular strikes with the Kusabimaru cannot permanently kill infested or undead beings (such as the Guardian Ape or Senpou High Priests); they will continuously resurrect. The Mortal Blade is required to execute specific Severance Deathblows to end immortal existences permanently.

Synergistic Combat Strategy: Combining Both Blades

Rather than choosing one sword over the other, optimal playstyles in Sekiro rely on seamlessly integrating the Mortal Blade into standard Kusabimaru combat:

• Opening Phase (Vitality Depletion): Bosses regenerate their Posture meter rapidly when their health (Vitality) is high. Players often begin encounters by using the Mortal Blade’s Mortal Draw during boss recovery windows to quickly reduce their Vitality below 50%.
• Main Phase (Posture Breaking): Once boss health is lowered, players switch back entirely to the Kusabimaru to land precise deflections, counter-attacks, and Mikiri Counters to fill the enemy’s Posture bar.
• Finishing Phase (Execution): The final Deathblow is initiated with the Kusabimaru, followed by a cinematic finish using the Mortal Blade if the target is an immortal entity.

Summary Checklist: Mortal Blade vs. Kusabimaru

• Primary Melee & Deflection: Kusabimaru (Zero cost, infinite usage, handles all parries and standard strikes).
• Guard-Piercing & Burst Damage: Mortal Blade (Consumes Spirit Emblems, pierces blocks, ideal for heavy openings).
• Immortality Killing Capability: Mortal Blade (Required for narrative execution of undead bosses).
• Equip Slot Alignment: Kusabimaru = Main Weapon Slot; Mortal Blade = Combat Art Slot (Mortal Draw).

In Sekiro: Shadows Die Twice, there is no single lootable "strongest weapon" in the traditional Action-RPG sense. Wolf’s primary melee weapon, the Kusabimaru, is irreplaceable and scales globally in power through Attack Power upgrades rather than weapon swaps. However, in terms of sheer damage output, guard-piercing capabilities, and Posture destruction, the Mortal Blade (specifically via the Mortal Draw and Empowered Mortal Draw Combat Arts) is universally recognized as the strongest offensive technique/weapon in the game, complemented by specialized Shinobi Prosthetic Tools for specific tactical match-ups.

The Dual Definition of "Strongest": Primary Sword vs. Burst Skill

Understanding what constitutes the "strongest weapon" in Sekiro requires separating sustained baseline combat from peak burst damage:

• Sustained Combat Core (The Kusabimaru): The Kusabimaru is the strongest—and only—tool for continuous defense, deflections (Parry), and Posture damage. Because it costs zero Spirit Emblems and handles 100% of incoming attacks, it is mechanically the most essential weapon in the game.
• Peak Offensive Damage (Mortal Draw via Mortal Blade): When evaluating raw damage potential per second (DPS) and guard-piercing capability, the Mortal Blade used via the Mortal Draw Combat Art outclasses every other action in Wolf’s arsenal. It forces massive Vitality and Posture damage even through an enemy's active guard.

Why Mortal Draw Is Considered the Peak Offensive Weapon

While the Crimson Mortal Blade (Fushigiri) cannot be equipped for basic light slashes, its execution via Mortal Draw acts as Sekiro's ultimate heavy weapon strike:

• Unblockable Guard-Piercing Damage: Most boss block animations negate standard Kusabimaru attacks. Mortal Draw bypasses physical guard frames, delivering high physical and magical shockwave damage directly to the opponent's Vitality bar.
• High Stagger Threshold: Hitting a boss or elite enemy with Mortal Draw frequently interrupts their ongoing attack animations, forcing a stagger animation that opens windows for follow-up strikes.
• Functionality at Zero Spirit Emblems: Although Mortal Draw normally costs 3 Spirit Emblems per strike, players can continue casting it even after running out of Emblems. The zero-Emblem version deals slightly less range and damage, but retains its core guard-piercing properties.

The Strongest Secondary Tools: High-Utility Prosthetics

Because Wolf cannot swap his primary katana, his Shinobi Prosthetic tools act as modular "secondary weapons." Certain upgraded Prosthetics deliver unmatched effectiveness against specific enemy archetypes:

• Loaded Axe (Sparking Axe / Lazulite Axe): The highest raw Posture-breaking tool in the game. It instantly shatters enemy wooden shields and inflicts massive posture damage against blocking humanoid targets.
• Flame Vent (Okinaga's Flame Vent): The strongest status-inflicting weapon. Applying the Burn status stops an enemy’s Posture recovery completely and leaves them immobilized in pain for several seconds.
• Firecracker (Long Spark): The ultimate crowd-control and boss-opening tool. Blinding enemies creates a guaranteed 2–3 second window to land unpunished heavy attacks or cast Mortal Draw.

How "Weapon Power" Scales in Sekiro

Unlike games where acquiring a late-game sword increases damage stats, weapon strength in Sekiro is governed entirely by system progression:

• Memory Enhancement: Defeating main story bosses grants Battle Memories. Presenting these at a Sculptor's Idol permanently increases Wolf's global Attack Power, which directly boosts damage dealt by both the Kusabimaru and the Mortal Blade.
• Lapis Lazuli Upgrades: Upgrading Shinobi Prosthetics to their ultimate Lazulite forms (such as the Lazulite Sacred Flame or Lazulite Shuriken) requires collecting rare Lapis Lazuli materials, representing the true physical upgrade tree in the game.

Summary Checklist: Sekiro's Strongest Arsenal Setup

• Most Essential / Strongest Defense: Kusabimaru (Infinite use, handles all deflections, builds enemy Posture meters).
• Highest Raw Offensive Burst / DPS: Mortal Draw (Mortal Blade Combat Art, pierces blocks, staggers bosses).
• Strongest Shield / Posture Breaker: Loaded Axe (Destroys defenses instantly).
• Strongest Boss Opening Tool: Shinobi Firecracker (Immobilizes targets for free attacks).

In the official, unmodded base game of Sekiro: Shadows Die Twice, no, it is not possible to obtain or equip the Black Mortal Blade as a playable weapon. The Black Mortal Blade (named Open Gate or Kaimon) is held exclusively by Genichiro Ashina (and later Sword Saint Isshin) as a lore and narrative boss weapon. While Wolf naturally obtains the Red Mortal Blade (named Gracious Gift of Tears / Bairai) as part of the main story, the Black Mortal Blade remains unplayable outside of third-party PC modifications (mods).

Understanding the Lore Distinction: Red vs. Black Mortal Blade

To understand why players cannot acquire the Black Mortal Blade, one must examine the specific lore and functional separation established by FromSoftware between the two Mortal Blades:

• The Red Mortal Blade (Gracious Gift of Tears / Bairai): Held by Wolf, this crimson blade possesses the primary power of Immortality Severance (Fushigiri). It is designed to kill immortal entities (such as infested monks, dragon-blood heirs, and corrupted beings) and harvest the Divine Dragon's tears.
• The Black Mortal Blade (Open Gate / Kaimon): Held by Genichiro Ashina, this obsidian blade possesses the supernatural power of Resurrection and Netherworld Summoning. Its inscription reads that by offering a sacrifice of dragon-blood heritage, it can open a gate to the underworld to resurrect a deceased warrior in their absolute prime.
• Narrative Alignment: Because Wolf’s goal is to sever the ties of immortality to protect Kuro, his narrative journey requires only the Red Mortal Blade. Obtaining the Black Mortal Blade would contradict the core plot line, as Genichiro uses it specifically to attempt to save Ashina from collapse.

Boss Encounters and Combat Mechanics of "Open Gate"

Although players cannot wield the Black Mortal Blade directly, they experience its combat capabilities firsthand during key endgame boss fights:

• Genichiro, Way of Tomoe (Genichiro, Ashina Outskirts): Before the final encounter with Sword Saint Isshin, Genichiro wields the Black Mortal Blade to cast black-and-crimson shockwave attacks (Mortal Draw variations) that inflict heavy chip damage through Wolf's deflects.
• Sword Saint Isshin: Following Genichiro’s sacrifice using Open Gate, Isshin Ashina is summoned from the underworld at the peak of his martial power, briefly using the Black Mortal Blade for wide sweeping dark energy strikes during Phase 1.
• The Shura Ending: In the Shura ending path, Genichiro is defeated off-screen by Emma and Isshin, leaving the Black Mortal Blade in the possession of the mortal Isshin before Wolf ultimately claims victory, though it remains unequipable afterward.

PC Modifications: How Players Wield the Black Mortal Blade

The primary reason for widespread confusion online regarding the playability of the Black Mortal Blade stems from community-created PC Mods:

• Cosmetic Mesh Swaps: Mods available on platforms like Nexus Mods allow PC players to swap the physical model and particle effects of the Red Mortal Blade with the Black Mortal Blade. This changes Wolf's Mortal Draw animation from crimson-red waves to the pitch-black shockwaves used by Genichiro.
• Custom Moveset Mods: Advanced mods (such as Ultimate Genichiro or Sekiro Resurrection) give players full access to Genichiro’s exact weapon animations, including the Black Mortal Blade's long-range Open Gate strikes.
• Console Limitation: On console platforms (PlayStation 4/5 and Xbox One/Series X), where mods cannot be installed, obtaining or wielding the Black Mortal Blade remains 100% impossible.

Summary Checklist: Black Mortal Blade (Open Gate) Status

• Playable in Official Base Game: No (Unobtainable by Wolf through story progression or secret quests).
• Owner / Wielder in Lore: Genichiro Ashina (and briefly Sword Saint Isshin).
• Primary Supernatural Ability: Underworld Resurrection (Open Gate / Kaimon).
• Playable via PC Mods: Yes (Model swaps and moveset mods allow visual and mechanical customization on PC only).