- spell effects, regardless of the type of damage will trigger on any source of damage which triggers
- Each spell cast will generate 10 charge.
- Moving by any means provides 5 charges for every 100 in-game units (approximately 1 Teemo diameter) traveled. This includes walking, using dash or blink abilities like Tristana's Rocket Jump or , or casting or being pulled or knocked back.
- The damage dealt by Luden's Echo will apply spell effects from items as an area of effect ability.
- Spell vamp is reduced to one-third effectiveness.
- will apply a 40% slow.
- Note that Luden's Echo does not affect the classification of the triggering ability - a single-target ability, such as Blinding Dart, is still treated a single-target ability for applying its own spell effects.
- Luden's Echo will not apply champion-specific spell effects, such as Blaze, nor duplicate the effects of a champion ability (e.g. Blinding Dart will not blind all enemies hit and Baleful Strike will not generate AP for every enemy hit).
- With large scale AoE effects, the item will pick a main target based on the pick order.
- Basic attacks under the following conditions will trigger Luden's Echo's damage, as they are considered spells that cause ability damage:
- Bard's Traveler's Call (meeps)
- Cho'Gath's Vorpal Spikes
- Ekko's Phase Dive
- Gragas' Drunken Rage
- Jax's Empower and Grandmaster's Might
- Katarina's Bouncing Blades when hitting a marked target
- Kayle's Righteous Fury
- Kennen's Electrical Surge
- Kha'Zix's Unseen Threat
- Leona's Shield of Daybreak
- Lux's Illumination when hitting a marked target
- Mordekaiser's Mace of Spades
- Sejuani's Flail of the Northern Winds
- Shen's Twilight Assault
- Twisted Fate's Pick A Card
- Udyr's Tiger Stance (activation effect) and Udyr's Phoenix Stance (persistent effect)
- This item was designed to replace the removed as the third high-end AP item.
- The name "Luden's Echo" was data-mined from the PBE update pushed on 2015-02-17. The item was later enabled for testing with placeholder name "Item 3285".
- The name "Luden's Echo" comes from a player who reached 1000 referrals on the old Refer A Friend system.
- During testing on the PBE, the item's icon was a purple recolor of .