TFT Set 18.1
Sentinel, a 4-cost Invoker unit in TFT Set 18

Sentinel

4 Magic Tank 
Azure Shockwave
Gain 530 / 734 / 2421 Ability PowerMax Health 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 Ability Power 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.
Shield
530 / 734 / 2421 Ability Power Max Health
Shield Duration
4
Take
100 / 150 / 3500 Ability Power
Mana Reave Flat
10
Trait Allies Mana Regen
2

Traits

  • Invoker 
    Your team gains Mana Regen, increased for Invokers.
  • Riftbeast
  • Vanguard 
    At Combat Start and after dropping below 50% Health, Vanguards gain a max Health Shield for 10 seconds.

Sentinel enables

  • Knock Up

    Briefly lifts the target into the air, interrupting their action. A unit that is knocked up cannot act, move, or cast until it lands.

  • Mana Reave

    Raises the Mana cost of the affected unit's next Ability cast, delaying that cast rather than preventing it. The unit keeps generating Mana at its normal rate — it simply needs more of it before the Ability goes off. That makes it a tempo debuff aimed at casters: it buys time instead of removing the cast, unlike a Stun, which interrupts one that is already happening.

  • Shield

    Grants temporary HP that absorbs damage before the unit's real Health is touched.

  • Mana

    The unit-level resource that gates ability casts — champions cast once their mana bar fills, so low-mana units cast more often than high-mana ones. Spear of Shojin (mana per attack) and Adaptive Helm (amplifies Mana from all sources) push casts faster, alongside starting-mana augments.

Sentinel benefits from

  • On Cast

    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.