Fire Mastery

Passive - increases all damage caused by your fire spells.

Fire Mastery is a Sorceress passive (Fire tree, level 30, no prerequisite) and the last skill in the tree. It costs nothing and casts nothing: it adds a percentage to the fire damage of your fire skills, +30% at level 1 and +7% a level after, and the one number that matters is the total, +163% at level 20.

The numbers

The whole skill is one line. The row's passivestat1 is passive_fire_mastery and passivecalc1 is ln12, which is Param1 (30, the table's "Damage % baseline") plus Param2 (7, "Damage % per level") for every level after the first: 93% at level 10, 163% at level 20, 233% at level 30. The expression reads lvl, so +skills from gear raise it like hard points; a +3 skills setup turns a level 20 mastery into +184%. There is no mana line.

How it works

The passive state "firemastery" carries the stat passive_fire_mastery while you have the skill. The Basin treats Fire Mastery and items' +% Fire Skill Damage as one bonus, see Fire Skill Damage, and says it normally applies to your fire skill damage after any synergy bonus: the synergies add to the skill's base, then the mastery multiplies the total. It also applies to melee fire attack damage, and the Basin's page on Enchant adds that in D2R it applies a second time to ranged attack damage too.

The Basin's page says the mastery is read when damage is applied or when a missile is created, so a skill with a delay between cast and damage (Meteor's fall, a Hydra's bolts) reads whatever mastery you have at that moment.

What it does not multiply, by the Basin's list: any pet the Sorceress summons except Hydra (whose row reads the caster's passive_fire_mastery for its bolts), Fire Arrow's converted damage, Immolation Arrow's damage per second, Molten Boulder's damage per second, Corpse Explosion, the Skeletal Mage's missile and the Fire Golem. It applies to Holy Fire's attack damage before it is added and to Enchant when cast, then again on a melee attack.

Synergies and +skills

Fire Mastery has no synergies and feeds no synergy line. Its whole effect is the percentage above, and that percentage reads lvl, so every +skill is worth exactly a hard point: +7%.

Against players

Fire Mastery is a passive on yourself and never touches a player. The fire hits it multiplies are cut to 17% of their value against a player by the player-versus-player rule, see Player versus Player.

Build notes

• Each point is +7% on every fire skill at once; past level 1 a point here is worth more than a point in any single synergy once more than one fire skill is in use.
• Because it reads +skills, the twentieth hard point and a +1 skills charm are the same +7%.
• It multiplies after the synergies, so it does not change which synergy is worth most; it scales whatever they produce.