What is magic damage in TFT, and how is it different from Ability Power?

Magic damage is a damage type . It is a tag on the hit that decides which resistance reduces it. Only Magic Resist reduces it. Armor does nothing. Ability Power is different. It is a stat on the unit dealing the hit. Each point adds 1% to that unit's ability effect. That covers damage, but also shielding and healing. So Ability Power raises magic damage dealt, but never turns physical damage into magic. Note: Abilities deal magic damage by default, apart from attack-modifiers. Nothing in the current set converts one damage type into another.

Which stats actually reduce magic damage — does Armor do anything?

No, Armor does nothing against magic damage. It only reduces physical hits. Magic Resist is the matching stat. Both resistances use the same formula: the damage multiplier is 100 divided by (100 + resist). 50 Magic Resist cuts about a third. 100 Magic Resist cuts half. Note: Type-blind layers still help. Durability reduces all damage taken. A shield is temporary health that takes damage before Health does, whatever the type.

Does all magic damage come from abilities?

No. Abilities are the usual source and deal magic damage by default. But attacks carry it too: Items and abilities add bonus magic damage on attack. An ability can replace attacks with magic hits. Damage over time can be magic too, though the Burn keyword deals true damage. So attack speed scales attack-attached magic damage. Note: Ability Power does not automatically raise item damage. An item's magic damage scales with it only where the item's own text prints that ratio.

Does Magic Resist cut only an ability's base number, or the Ability-Power-scaled total?

The whole total . A resistance is a damage multiplier: 100 divided by (100 + Magic Resist). It is applied to each finished hit. So it removes the same percentage from a big instance as from a small one. Extra Ability Power cannot out-scale it. Damage Amp, by contrast, applies after mitigation. Cutting the target's Magic Resist helps every magic hit your board lands on it. Ability Power helps one unit. Note: One correction: ability damage does not critically strike by default. It needs Precision.

My ability carry has the right items but deals almost no damage — what is going wrong?

Usually one of four mechanic-level causes. It is not casting. Most units cast only when the mana bar fills, and mana comes from attacking and from taking damage. The enemy stacks Magic Resist and nothing on your board applies Shred. Targeting sends basic attacks at the closest enemy, usually a tanky one. Many abilities use their own targeting rule, though. The damage is spread across many enemies and kills none.

If the enemy's Magic Resist is cut after my carry already cast, does that damage get bigger?

No. A resistance is a multiplier applied as each hit lands, against the target's Magic Resist at that moment. Damage already dealt is not recalculated. Shred lasts for a set duration . So only hits arriving inside that window are cheaper. Ordering matters: the Shred source should land before your burst. Note: A single big cast gains nothing from a cut that arrives late. Repeated hits and damage-over-time ticks keep benefiting while it runs.

Should my board stick to one damage type, or mix magic and physical?

Both work. Armor and Magic Resist use the same formula: 100 divided by (100 + resist). So neither damage type is inherently stronger. The enemy's defences decide it. A single-type board is answered by stacking one resistance. A mixed board leaves either resistance only half useful. Note: The trade-off is resist-cutting. Shred lowers Magic Resist and Sunder lowers Armor, each only its own. One type means one debuff lifts the whole board. Splitting means you need both.

Does the magic tag change anything besides which resistance applies?

Mostly no, with one correction. The type decides which resistance applies, not which triggers fire: Magic damage feeds omnivamp healing. Shields absorb it like any other damage. It carries no built-in anti-heal or bypass. The correction: it does not crit by default. Basic attacks can critically strike, while ability damage needs Precision. Note: True damage is the type that ignores resistances. Magic damage does not.