Description
This effect triggers the instant a unit casts its ability. Items like Lich Bane and the Invoker Emblem reward you for landing as many casts as possible.
Items (4)
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- +10% AS
- +55% AP
The holder’s first attack after each Ability cast deals a Stage-scaled amount bonus magic damage. Damage increases based on Stage.
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- +15% AD
- +15% AP
- +1 Mana Regen
After casting the first time in combat, gain 110 Mana over 5 seconds.
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- +3 Mana Regen
The holder gains the Invoker trait. On cast, gain Ability Power equal to 10% of Mana spent.
Your team gains Mana Regen, increased for Invokers.
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- 1 Mana Regen | 3 Mana Regen
- 3
- 1 Mana Regen | 4 Mana Regen
- 4
- 2 Mana Regen | 6 Mana Regen
- 5
- 2 Mana Regen | 9 Mana Regen
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- +25% AP
The holder gains the Spellweaver trait. Gain 2 Mana whenever an ally casts their Ability.
Your team gains 10% Ability Power. Spellweavers gain more, plus extra Ability Power whenever a Spellweaver casts an Ability.
- 2
- 10% , +1% per cast
- 4
- 30% , +1% per cast
- 6
- 55% , +2% per cast
Augments (1)
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Unrivaled Gold You can field Rengar and Kha'Zix together with no penalties, and they gain bonuses when the other casts. Gain a Rengar and a Kha'Zix.
Champions (17)
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Razor Leaves Summon five razor-sharp leaves that converge on the current target, dealing a total of 370 / 555 / 835 physical damage and applying 20% Wound and 1% Burn for 4 seconds. Scarlet Buff: Cinderling gains 22% Attack Damage each cast. Wound: Reduces healing received. Burn: Deals a percent of the target's max Health as true damage every second. -
Uproot Passive: Restore 17 / 27 / 43 Health each second, tripled for 3 seconds after casting. Active: Lunge out of the ground, Stunning adjacent enemies for 1 second and dealing 70 / 105 / 160 magic damage to them. -
Spider Queen Transform into a spider and gain 375 / 475 / 725 max Health. Attacks while in Spider Form deal 35 / 50 / 80 bonus magic damage and heal for 55 / 90 / 170 . Subsequent casts grant 175% decaying Attack Speed for 4 seconds.
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Fungus Among Us Throw 2 clusters of mushrooms that deal 60 / 90 / 135 magic damage to the 3 nearest enemies. Then hurl a giant mushroom that deals 135 / 200 / 310 magic damage to the target. Each cast has a 10 / 12 / 15% chance to forage an extra mushroom that can be collected for bonus effects. Red: 1 Reroll Green: 1 Tactician Health Yellow: 2 XP
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Forest's Flurry Blink away from the current target, deal 235 / 355 / 1200 physical damage to them, and gain 30 / 30 / 100% Attack Speed. Every 4th cast consumes the Attack Speed granted from Nature's Wrath and fires a blast through the largest group of enemies that deals 385 / 580 / 2500 physical damage, reduced by 25% for each enemy it passes through (minimum 50%).
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Azure Shockwave Gain 530 / 734 / 2421 Shield for 4 seconds. Slam the ground, sending a fissure in the direction of the most enemies. Enemies hit are briefly knocked up, take 100 / 150 / 3500 magic damage, and are Mana Reaved for 10. Blue Buff: Each time Sentinel casts, allies gain 2 Mana Regen. Mana Reave: Increase the Mana cost of the next Ability cast.
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Triggerseed Passive: Shields from this Ability can critically strike with Precision. Active: Grant 2 / 2 / 10 allies 165 / 300 / 3000 Shield and 10 / 15 / 100% Damage Amp for 6 seconds. Then deal 140 / 210 / 2000 magic damage to enemies adjacent to them. After casting 6 times, also grant 100% stacking Attack Speed to targets.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the largest group of enemies that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Blackthorn Bonus: Stuns targets hit for 1 second.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Blossom Bonus: The first target hit is dealt 10% bonus damage.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Coven Bonus: Reduces the Armor and Magic Resist of targets hit by 8 for the rest of combat.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Elderwood Bonus: Casts grant all allies 2.5% increased max Health for the rest of combat.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Fae Bonus: Heals the lowest percent Health ally for 18% of ability damage dealt.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Inferno Bonus: Restores 10 mana per takedown.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Lunar Bonus: Applies 10% Vulnerable to enemies hit for 4 seconds. Vulnerable: Increases damage taken
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Primal Bonus: Gain 60% Attack Speed for 6 seconds after cast.
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Final Spark Passive: On cast, all allies that share a trait with Lux gain 3 / 3 / 100 mana. Active: Fire a laser towards the most enemies in a line that deals 330 / 520 / 5000 magic damage, reduced by 25 / 25 / 10% for each enemy hit (minimum 40%). Solar Bonus: Deals 12% bonus damage for each unique 3-star champion fielded.
More On Cast sources
What enables On Cast (1)
Traits (1)
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Your team gains 10% Ability Power. Spellweavers gain more, plus extra Ability Power whenever a Spellweaver casts an Ability.
What benefits from On Cast (2)
Traits (2)
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Your strongest Alune cycles to a new phase of the moon after each cast. While the moon is at or below half full, your team gains 7% Durabilty. While above, your team gains 7% Damage Amp.
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Gain 1 seed when your strongest Ivern casts, plus 3 every combat. Ivern uses 5 seeds to grow a hex on your board that grants a bonus to its occupant.
Frequently asked questions
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What does "on-cast" actually mean in TFT?
On-cast effects fire the moment a unit casts its Special Ability — i.e. the same instant the mana bar empties and the ability triggers. TFT abilities have no cooldowns; the only gate on the cast is the mana bar filling, so any item, trait, or augment text that says "on cast," "each cast," or "after casting" hooks into that single ability-fired event. The wiki notes most ability casts complete in roughly 0.5 seconds, so on-cast effects feel near-instant in practice.
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What kinds of effects are wrapped in "on cast" text?
The most common on-cast payloads are: a flat or percent mana refund / starting-mana reset, a chunk of healing or shielding, a stacking damage amp on the next attack, and a buff to nearby allies scaled by mana spent. Two recurring item archetypes are the "first-attack-after-cast deals bonus magic damage" item and the "each cast restores a percent of maximum Health over a few seconds" locket — both classes are gated entirely on the cast event, so neither does anything before the unit casts at all.
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How does mana-on-cast / mana refund work?
Some on-cast effects bank a chunk of mana straight back into the bar so the next cast comes faster. The classic shape is a fixed post-cast set — an item or trait that says "after casting, set mana to N" — which guarantees the second cast starts much closer to its threshold than a normal post-cast reset would. (This exact shape has rotated in and out of specific items across patches — an item that carried it in one set may be reworked into something else entirely in the next — so check current tooltips for which item, if any, actually ships the mana-set shape in the set you're playing.) On-cast mana that would push the bar above its max also carries over to the next cast (the wiki's worked example: 50/60 + 20 = 10/60 after casting), so a refund plus overflow can accelerate the next cast by more than the printed number.
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Does an on-cast effect still trigger if my unit is stunned before it casts?
No — a stunned unit "is unable to move, declare attacks, or cast their Special Ability for the duration," so if crowd-control lands while the bar is full but the cast hasn't gone off yet, the cast is suppressed and nothing on-cast triggers. The cast event is what the on-cast hook listens for; no cast, no trigger. Once the stun ends a fully-charged unit will cast at the next available frame and on-cast effects fire then.
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Do bonus casts from multi-cast traits each trigger on-cast effects?
When a set ships a multi-cast trait, it typically makes a unit's ability occur an extra time at reduced effectiveness — the bonus occurrence reruns the ability at a reduced payload. Whether every secondary item-level on-cast hook re-fires on that bonus occurrence is not exhaustively documented — community-observed behavior is that they do, but treat it as patch-volatile and verify against the live patch notes for the set you're playing.
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If a unit holds two on-cast items, do both trigger on the same cast?
Yes — different on-cast effects from independent sources (two distinct items, an item plus a trait, an augment plus an item) each listen for the same cast event and resolve in parallel when it fires. What does NOT necessarily double up is the *same* item equipped twice: TFT generally restricts duplicate Artifact equips, and for items with shared multi-second timers the wiki history shows Riot has previously added cooldown-style guards specifically to stop multiple identical on-cast heals from stacking unbounded.
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Is "on-cast" the same as "post-cast" or the mana-lock window?
They overlap but aren't the same. On-cast is the trigger event — fired the instant the ability resolves. The mana-lock window is the brief no-mana-gain period that begins right after that cast (a mana-lock window of roughly a second, longer for some long-channel champions); it's about gating when the bar can start refilling, not about firing effects. So an on-cast item resolves first, then the mana-lock clock runs, then the bar starts filling again — and any on-cast mana refund is applied before the lock starts ticking.
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Do on-cast items do anything on a manaless unit?
No. A manaless unit has no mana bar and "never casts a triggered Special Ability — instead it has a permanent passive effect that's active for the entire combat," so there is no cast event for an on-cast effect to hook into. Items whose payload is gated entirely on a cast (first-attack-after-cast bonuses, heal-on-cast lockets, mana-refund items, on-cast shield/buff effects) do nothing on a manaless holder. Whether any given set even ships manaless units rotates set-to-set.