Chain Lightning

Creates a bolt of lightning that arcs through several targets.

Chain Lightning is a Sorceress Lightning skill (level 18, requires Lightning) and the prerequisite of Thunder Storm and Energy Shield. It is a bolt that hits a target and jumps to the next one within range, again and again, until its hits are spent. Two numbers decide it: the damage range, 1 to 281 at level 20 before synergies, and the number of hits, 5 at level 1 and 9 at level 20, one more every five levels.

The numbers

The minimum is 1 at every level: EMin is 1 and every EMinLev column is 0. The maximum comes from EMax with HitShift 8: 40 at level 1, then +11 a level to level 8, +13 to 16 and +15 a level past that. That is 1–143 at level 10, 1–281 at level 20 and 1–431 at level 30. The line reads lvl, so +skills count.

The hits are calc1, ln34/par5: Param3 26 (the table's "# of target jump hits baseline") plus Param4 1 a level ("# of target jump hits per level"), divided by Param5 5 ("Every # levels, increase target jump") and rounded down. So the count steps up at levels 4, 9, 14, 19, 24 and 29: 5 hits at level 1, 7 at level 10, 9 at level 20, 11 at level 30. It reads lvl, so +skills add hits.

Mana is 9 at level 1 and 1 more a level (mana 9, lvlmana 1, manashift 8): 18 at level 10, 28 at level 20, 38 at level 30. The jump radius never changes and is not in the table: Param1 20 ("Radius of jump to next target", aurarangecalc par1), which is 13.33 yards.

How it works

Chain Lightning fires one "chainlightning" missile; the Basin's page classes it as a long-range multi-missile cast. When the bolt hits a target it looks for another target within 13.33 yards and arcs to it; if there is none, the Basin says, the bolt travels harmlessly off-screen and the remaining hits are wasted. It is lightning damage, reduced by the target's lightning resistance, see Dealing Elemental Damage and Resistances and Immunities; as a spell it needs no attack rating. It is cast at casting speed and the Sorceress's Faster Cast Rate breakpoints.

The Basin's page gives the rule for chaining back to a target already hit: Chain Lightning has a next-hit delay of 4 frames, and the bolt will only return to a target if that delay has expired before it reaches it again; otherwise it passes through and off-screen, breaking the chain. Two targets close together can therefore be worse than two far apart. The lightning drawn on the screen does not necessarily correspond to the targets hit.

The Basin's page says the skill level is applied when cast, but Lightning Mastery and other +% lightning skill damage are applied to each link as it is created; a weapon swap between cast and the last link changes the later links.

Synergies and +skills

• Charged Bolt: +4% lightning damage per level, Nova: +4% lightning damage per level and Lightning: +4% lightning damage per level (skills.txt Param8 = 4; the calc reads each skill's blvl, hard points only).
• The Basin's page notes the synergy bonuses do not apply to the minimum damage, which stays at 1.
• Chain Lightning in turn feeds Lightning at +8% a hard point, twice what it receives from Lightning.
• +skills raise the maximum and the hit count (lvl); none of the percentages move with +skills.

Against players

A player's hit on another player is cut to 17% of its value (difficultylevels.txt PlayerDamagePercentVSPlayer) before anything else, see Player versus Player. The Basin's page gives no other rule for Chain Lightning against players.

Build notes

• Three synergies at 4% each are half of what the same three skills give Lightning (8%), while Chain Lightning gives Lightning 8%: a point in Chain Lightning does more for Lightning than a point in Lightning does for Chain Lightning.
• The 9 hits at level 20 are the real multiplier: against a pack, 9 × 1–281 before synergies, for 28 mana.
• The next hit comes at level 24 and the one after at 29, so +skills past 20 buy hits as well as damage.
• The minimum of 1 never moves, so the bolt's hits land for very different numbers.