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Orb of Corrosion
Stats
Abilities
Corrosion
Your attacks reduce the target's armor by -2, slows their movement by -16% (-8% against melee targets), and reduces Health Restoration by 16%. Lasts for 3 seconds.
Strategy
Why Buy Orb of Corrosion?
Think of it as Orb of Frost's bigger, meaner sibling. Same core idea—every attack applies a debuff that slows and reduces health restoration—but Orb of Corrosion adds armor reduction and damage over time on top of that. Four different things happening on every single attack, passively, for under a thousand gold. That is an absurd amount of laning pressure per gold spent.
The armor reduction is what makes it genuinely dangerous early. Hitting someone for slightly more damage is one thing. Stripping their armor while you do it means every subsequent hit in that exchange also deals more damage. Against a carry who is already losing the trade, Orb of Corrosion makes every second they stay in range exponentially worse for them.
The health restoration reduction now covers everything after 7.41—regeneration, lifesteal, spell lifesteal—all of it reduced simultaneously. Against a hero trying to sustain themselves through your harassment with a Ring of Health or any lifesteal, Orb of Corrosion is quietly undoing their recovery every time you land an attack.
When to Buy Orb of Corrosion?
Early laning phase on melee cores who want to bully, trade, and deny enemy sustain before the game develops. The melee slow is notably stronger than the ranged slow, so this item rewards aggressive melee heroes who want to be in the enemy's face constantly. Lifestealer, Ursa, Abaddon, and Batrider—heroes who attack frequently and up close—get the most out of every component of the debuff.
The comparison to Orb of Frost is worth making directly. Orb of Frost is cheaper and simpler. Orb of Corrosion costs roughly three times as much but gives you agility, armor reduction, and damage over time that Orb of Frost does not. If your hero already transitions toward a build where the extra agility and armor shred matter—and many melee cores do—Orb of Corrosion is the correct buy. If you just want a cheap, slow one and the Orb of Frost component fits your upgrade path, start there first.
Skip it when your hero is ranged—the slow on ranged heroes is significantly weaker, and most of the value is concentrated in the melee version of the debuff. Also skip it when your build already has a stronger armor reduction source later that will make the corrosion redundant.
Tips & common mistakes
- Orb of Corrosion and Orb of Frost do NOT stack. If you somehow have both, only the higher flow applies. Never buy both—it is pure waste.
- The damage over time is direct HP removal. It does not trigger on-damage effects, it is not blocked by damage block, and it is lethal. A target at low HP who you cannot reach can still die from the corrosion ticking down if they are already in range of the debuff duration.
- Reapplying the debuff refreshes the duration. In a prolonged laning trade where you land three or four attacks, the target has been armor-reduced and slow-affected for the full duration of the last hit—not just the first one. Keep attacking.
Summary
Orb of Corrosion is what you buy when Orb of Frost is not enough. Slow, armor reduction, damage over time, and health restoration reduction every attack—all under a thousand gold—on a melee core who is going to be in someone's face all game anyway. The debuff compounds with every follow-up attack. Buy it early, abuse the laning phase, and watch enemy carries stop trying to trade with you.
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Lore
Seepage from the wounds of a warrior deity, sealed in an arcanist's orb following a campaign of vicious slaughter.