Which attacks count

Four different things land as an attack, and they do not all trigger the same effects. This is the difference between a card that works in your build and one that never fires.

auto-attack
Your ordinary weapon swing. Triggers everything - on-hit effects, Nth-hit counters, and full weapon damage.

multi hit
Extra targets struck by one swing. Each extra triggers your on-hit effects and deals reduced damage. All of them share the swing's critical hit roll.

spell strike
A swing created by a spell rather than aimed by you. It triggers your on-hit effects at full strength and deals full damage, but it does NOT count toward Nth-hit counters.

phantom strike
A phantom copy of you. It deals no damage of its own, but it triggers every one of your on-hit effects and cannot fail their chance rolls.