Effect: 27% chance to apply a stack of Bloodmark on hit. Bloodmark deals damage to the enemy 5 seconds after being applied. The 5-second delay resets on each re-application. If the damage would exceed the enemy's current HP, it fires instantly.
Unlock: Available from the start - no unlock required
Unstable Transfusion is a Rare item that applies Bloodmark stacks to enemies on hit. Each stack builds an execute threshold displayed as a dark red region on the enemy's HP bar. When the enemy's HP drops into that region, they are instantly killed - they do not need to be reduced to zero HP.
The more stacks you apply, the higher that threshold climbs. Against a boss with a massive HP pool, enough Bloodmark stacks can push the threshold so high that the boss dies at 50% HP or more - shaving off an enormous portion of what would otherwise be a long, dangerous fight.
Each stack has a 5-second timer before it fires. That timer resets every time you apply another stack to the same enemy. This means that if you are hitting consistently, the stacks keep refreshing rather than ever actually firing - the damage only resolves when you stop hitting or when the execute threshold is reached and the enemy dies instantly.
Bloodmark is the status effect applied by Unstable Transfusion and Bloody Cleaver. Here is exactly how it works, including two things the wiki explicitly corrects as common misconceptions:
| Property | Details |
|---|---|
| What it does | Creates an execute threshold on the enemy's HP bar. When HP drops into the marked region, the enemy dies instantly. |
| Damage scaling | Scales with your level and your Damage stat. More Damage stat = higher execute threshold per stack. |
| Crit interaction | Bloodmark damage cannot crit and does not deal increased damage if applied by a crit hit. Crits are irrelevant to Bloodmark. |
| Lifesteal interaction | Bloodmark does NOT provide healing and has NO synergy with Lifesteal. That synergy is exclusive to Bloody Cleaver. |
| Best tome pairing | Damage Tome, not Precision Tome. Bloodmark scales with Damage stat, not crit - investing in Precision Tome wastes points for a Bloodmark build. |
| Applies to | All enemies including bosses. Bloodmark is one of the most effective tools for shortening boss fights. |
A very common misconception confirmed by the wiki: Bloodmark is a pure damage effect with no healing component. Unstable Transfusion has no synergy with Lifesteal. If you want Lifesteal from Bloodmark, that is exclusively from Bloody Cleaver, which ties Lifesteal hits to Bloodmark stack application. Do not stack Lifesteal Tome expecting it to interact with Unstable Transfusion - it does not.
No unlock required. Unstable Transfusion is available in the default item pool from the start of the game and can appear from Treasure Chests and the Shady Guy NPC on any run. As a Rare item it drops more frequently than Epic and Legendary items. Multiple copies can be found in a single run - each additional copy increases the 27% Bloodmark chance, eventually rolling multiple stacks per hit once the total exceeds 100%.
Vlad - Vlad is the most directly tied character to the Bloodmark ecosystem. Bloody Cleaver - the item that supercharges Bloodmark by converting Lifesteal into Bloodmark stacks - is unlocked by reaching Level 50 as Vlad. Vlad's Vampire passive gives +1% Lifesteal per level, meaning his Blood Magic weapon constantly heals him on every hit. With Unstable Transfusion applying Bloodmark stacks and Bloody Cleaver converting those lifesteal heals into additional stacks, Vlad applies Bloodmark at a rate no other character can match through passive gameplay.
Ninja - Ninja's playstyle centers on high-speed melee with an execute mechanic in his passive. The Bloodmark guide specifically calls out Ninja and high-attack-speed melee characters for their ability to stack Bloodmark rapidly on bosses through constant close-range contact. Ninja's execute passive also fires alongside Bloodmark's execute threshold, creating two independent sources of boss execution in the same build.
Bandit - The wiki explicitly states Attack Speed is one of the best stats for Bloodmark, as it provides more proc opportunities per second. Bandit's passive adds +1% Attack Speed per level, generating more 27% Bloodmark rolls every second than any other character without specific attack speed items. In a high-curse Bandit run against dense enemies, Bloodmark is applied so frequently that bosses enter the execute zone within seconds of spawning.
Bloodmark creates an execute threshold displayed as a dark red region on an enemy's HP bar. When the enemy's HP drops into that region they are instantly killed, without needing to reach zero HP. Each Bloodmark stack raises the threshold higher. Stacks are applied by Unstable Transfusion (27% on hit) and Bloody Cleaver (50% on hit, plus from Lifesteal). Bloodmark scales with your level and Damage stat.
Bloodmark is a status effect that builds an execute threshold on enemies. It is not an item itself - it is applied through Unstable Transfusion and Bloody Cleaver. The wiki describes it as strictly a damage effect with no healing component, despite what many guides claim.
No. The wiki explicitly corrects this misconception: Bloodmark is purely a damage effect and does not provide any form of healing. Unstable Transfusion has no synergy with Lifesteal. The Lifesteal and Bloodmark interaction exists only in Bloody Cleaver, which converts Lifesteal heals into Bloodmark stacks as a separate mechanic.
No. Bloodmark cannot crit and does not deal increased damage when applied by a crit hit. The wiki is explicit on this point and recommends Damage Tome over Precision Tome for Bloodmark builds precisely because crit investment provides no benefit to Bloodmark damage.
It gives each hit a 27% chance to apply a Bloodmark stack to the enemy. Each stack builds an execute threshold on the enemy's HP bar. The Bloodmark damage fires 5 seconds after the last stack was applied, but if the enemy's current HP is already in the execute zone, it fires instantly. Multiple copies increase the proc chance - once it exceeds 100%, multiple stacks can be applied per hit.
