Lightning Mastery

Passive - increases all damage caused by your lightning spells.

Lightning Mastery is a Sorceress passive (Lightning tree, level 30, no prerequisite) and the last skill in the tree. It costs nothing and casts nothing: it adds a percentage to the lightning damage of your lightning skills, +50% at level 1 and +12% a level after, and the one number that matters is the total, +278% at level 20, the largest of the three masteries.

The numbers

The whole skill is one line. The row's passivestat1 is passive_ltng_mastery and passivecalc1 is ln12, which is Param1 (50, the table's "Damage % baseline") plus Param2 (12, "Damage % per level") for every level after the first: 98% at level 5, 158% at level 10, 278% at level 20, 398% 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 +314%. There is no mana line.

How it works

The passive state "lightningmastery" carries the stat passive_ltng_mastery while you have the skill. The Basin treats Lightning Mastery and items' +% Lightning Skill Damage as one bonus, see Lightning Skill Damage, and says it normally applies to the Sorceress's lightning 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 lightning attack damage. The Basin warns that the character screen shows the mastery applied to ranged lightning attack damage as well, but that this is not actually the case.

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 reads whatever mastery you have at that moment; the Basin's page on Chain Lightning says each link is created with the mastery of that instant, and Thunder Storm's strikes are multiplied as they happen, for the whole 600-second duration of a level 20 storm.

What it does not multiply, by the Basin's list: any pet the Sorceress summons, and [[static-field]], whose cut of 25% of current life is not damage the mastery can scale. It applies to Holy Shock's attack damage before it is added, then again on a melee attack.

Synergies and +skills

Lightning 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: +12%.

Against players

Lightning Mastery is a passive on yourself and never touches a player. The lightning 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 +12% on every lightning skill at once; past level 1 a point here is worth more than a point in any single synergy once more than one lightning skill is in use (Lightning's synergies are 8% each, Chain Lightning's 4%).
• Because it reads +skills, the twentieth hard point and a +1 skills charm are the same +12%.
• It multiplies after the synergies, so it does not change which synergy is worth most; it scales whatever they produce. It does nothing for Static Field.