Unending Despair

Stats

Values as the League of Legends Wiki's item data lists them, for every mode; the data doesn't state their units.

Effects

• Anguish (unique): Every 4 seconds after entering combat with champions, sap all enemy champions around you within cr 650 units to deal magic damage equal to 3% of your bonus health to them and heal yourself equal to 250% of the post-mitigation damage dealt.³

Arena changes

• Health changed to 350.
• Ability haste changed to 10.
• New Effect: Anguish deals 15 to 25 base damage.
• Anguish health ratio changed to 3% bonus health.⁴

• Against an AD lane, build Bami's Cinder, then Unending Despair or a similar item rather than Sunfire.⁵

• Riftmaker's damage amp passive increases Unending Despair's damage and healing.⁶
• Unending Despair continues to heal while you are in Zhonya's, and Apex Inventor can reduce its cooldown.⁷
• Unending Despair counts as spell damage.⁸⁹
• With Apex Inventor, Unending Despair can trigger about every second.^89101112
• Unending Despair can trigger Pyromancer about every second.¹³
• With Unending Despair, fully souled Dragonheart, and Kinkou, walking in a circle around opponents without attacking or using abilities can kill them.¹⁴
• Unending Despair can proc Liandry's and reset its duration when it triggers again while you are in combat.¹⁵
• Unending Despair can proc Elder Soul.¹⁶

Earlier formats

• Unending Despair's damage and healing ticks continued while its wielder was in Zhonya's.¹⁷ 8x2 duos
• A build for Sett, AP bruiser tank Udyr, and Dr. Mundo paired Heartsteel with Bloodmail, Riftmaker, Unending Despair, Liandry's, and Spirit Visage.¹⁸ 8x2 duos