TFT Set 18.4 Positive effects you can stack on your own units. Each entry below links to the mechanic page where every Set 18 champion, trait, item, and augment that grants the effect is enumerated.
See also: Debuffs — negative effects you can apply to enemies — and Economy for player-side resource mechanics.
Who buffs allies: Team buffs lists only the champions, items, augments and traits that give these effects to other units.
Keep your units alive. From outright damage avoidance (Untargetable, Invulnerable, CC Immune) through HP buffers (Shield, Heal, Health Regen, Max Health) to flat damage mitigation (Armor, Magic Resist, Durability).
Untargetable is a protective state where the unit stops being a valid target.
Anything that has to pick a target cannot select it. That includes basic attacks and ability targeting.
Two things do not change:
It is often triggered by HP-threshold trait passives or by item effects.
Note: It is distinct from invulnerability. Invulnerability blocks damage but still allows targeting.
Invulnerable is a state that prevents all incoming damage for a duration.
The unit can still be targeted and attacked. It just takes no damage.
Note: It is distinct from Untargetable, which prevents the unit from being targeted at all.
CC Immune is a protective state where the unit ignores incoming crowd control for a duration.
Crowd control means effects like stuns, slows and taunts. Card text calls it Unstoppable.
The unit can still be targeted and damaged.
Note: Two other states look similar but are not the same.
A Shield is temporary HP that sits on top of a unit's real Health.
Damage hits the shield first. The unit's real Health is only touched once the shield is gone.
A Heal restores Health to a unit.
It cannot raise the unit above its maximum HP.
Health Regen is a Passive effect that restores Health every second.
It is usually a percentage of max Health.
It is separate from two other kinds of sustain:
The wearer simply regenerates over time.
Max Health is extra maximum HP given to a unit.
It comes in two shapes:
You meet it whenever you:
Old Growth permanently raises the max Health of your strongest Old Growth champion. It does so every time an enemy dies near it.
Note: That last kind never resets. Stats that keep growing round after round, Old Growth's Health included, have their own page: Permanent Takedown Stacks.
Armor is the physical-defense stat that reduces incoming Attack Damage (AD) damage.
Three kinds of sources feed into it:
A handful of effects also scale a bonus off a unit's Armor value.
Note: Sunder is its inverse, a debuff that reduces enemy Armor.
Magic Resist is the magic-defense stat that reduces incoming Ability Power (AP) damage.
Sources that grant it or scale off it:
Note: Shred is its inverse.
Durability is a percentage damage reduction that cuts incoming damage.
It applies after Armor and Magic Resist and stacks multiplicatively.
Sources include the following.
Combat-stat boosts that increase the damage your units deal — auto-attack speed, ability power, percent damage amp, omni-vamp sustain, crit, and stacks that ramp a unit up mid-fight or on a takedown.
Bonus Attack Speed (AS) makes a unit attack more often per second.
That gives two things.
Some carries scale beyond that. Their ability itself fires more hits when they have more Attack Speed.
Example: The number of swipes in Aphelios's onslaught grows with his Attack Speed.
Note: Stacking AS items and traits on these units compounds. You get faster autos, faster casts, and bigger casts.
Ability Power (AP) scaling means an effect gets stronger when its holder stacks AP.
Champions and effects flagged as AP-scaling get bigger damage, healing, or shield values.
AP comes from items like these, or from trait bonuses.
Damage Amp is a multiplicative bonus to all damage dealt.
It is not the same as raw Attack Damage (AD) or Ability Power (AP). AD and AP are type-specific scaling. Damage Amp applies after that type-specific scaling.
Omnivamp heals a unit for a percentage of the damage it deals.
The stat counts every damage type. Attacks and abilities both feed it.
Note: A few carriers use a smaller pool. Wit's End heals only from the magic damage it adds. They still count as Omnivamp: the same heal-from-your-own-damage effect, with a smaller pool to draw from.
Crit means a unit's damage scales with crit chance and crit damage.
Those stats come from items like Infinity Edge and Jeweled Gauntlet.
Note: By default, abilities cannot crit. The sibling Precision mechanic is what lets spell damage roll crits. So a crit-on-spell build needs a Precision source first. Only then do crit chance and crit damage apply to abilities.
Stacking In Combat means a unit ramps its power within a single round.
Two examples show the shape.
Note: All in-combat stacks reset when the round ends. Permanent takedown stacks are different. They carry across rounds.
Permanent Takedown Stacks are stat gains that keep growing round after round instead of resetting when the fight ends.
The usual trigger is a takedown. The unit banks a stack on every kill or assist and keeps it. So early-round farming compounds into late-game power.
But the trigger is not always a takedown you made.
Note: What every source here shares is the persistence, not the kill. The stack survives the round. That is what separates it from in-combat stacking, which starts again from zero every fight.
Repositioning effects that relocate a unit during combat. Dash is self-movement; Pull drags a target toward the source. The mechanic pages enumerate every ability that triggers each.
Dash is a repositioning movement that breaks normal movement.
It comes in two shapes.
Units use it for three things.
Pull is forced horizontal movement that drags a target toward the source.
The pulled unit does not move itself. Another unit's effect moves it.
Note: Two other movement effects are different.