Hits and damage

Hit events

Event Runs when
When player hits a player damages a mob, animal or player
When mob hits one of the Mobs damages a mob, animal or player
When entity is hurt a mob, animal or player takes damage

Mobs left empty runs for every mob, animal and player.

Hit with on When player hits picks melee hits or projectiles the player shot, of any kind or one kind. A thrown snowball or fired arrow of that kind counts.

When mob hits counts hits by hand and with a projectile. Its entity inputs left unwired take the hit entity. Wire Attacker to act on the mob that hit.

Hurt by on When entity is hurt picks one kind of harm: fall, fire (lava too), drowning, explosion or projectile. For hits by a player or mob, use When player hits or When mob hits.

Changing the hit

These act on the hit the event runs for.

Step Does
Change damage multiplies, adds to or sets the damage. Multiply 0.5 halves it. Set 0 lets the hit land with no damage.
Cancel event stops the damage
Damage on the hit entity, adds to the hit, which keeps its attacker
Kill on the hit entity, makes the hit kill, which keeps its attacker. A shield or totem can still stop it.

For half fall damage, use When entity is hurt with Hurt by fall, then Change damage.

Deaths

When entity dies runs when a mob, animal or player dies. Cancel event there keeps it alive.

When player kills runs when a player kills a mob, animal or player.

Kill with How set to remove takes a mob away without drops or a death. Players are only killed.