Chain Lightning

Version 0.28: This article may not be up to date for the latest stable release of Crawl.

Chain Lightning
Level	9
School1	Air
School2	Conjuration
Source(s)	Book of Annihilations
Casting noise	25
Spell noise	10
Power Cap	200
Flags	Area

Releases a massive electrical discharge that arcs to the creature nearest the caster and then outward from it. The further it travels, the less damage it does. Secondary arcs have limited range and do little damage to the caster. The spell's damage partially bypasses armour and resistance to electricity. “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -traditionally attributed to Samuel Clemens.

Spell Details
Damage Formula	3d(2*Power/3) electricity
Max Damage	3d133
Max Power	200
Range	LOS
Targeting	LOS
To-hit	Automatic
Special	Partially irresistible

Chain Lightning is a devastating but unwieldy level 9 Conjurations/Air Magic spell which unleashes a massive surge of electricity. When cast, it leaps from target to target, always going outwards. Its damage decreases as targets get further away. There is no way to actually aim the spell - when cast, the surge simply comes into being, blasting the nearest target and wreaking havoc among nearby units until its power is spent and it grounds out. Any unit in LOS, including you and your allies, is treated as a valid target, even if the target is invisible.

Also, the spell has a tendency to deal damage to the caster, though much less than it inflicts on enemies. With rElec, this damage is almost negligible, rarely reaching beyond single digits. With decent AC, it's even less of a concern. Casters with low AC and no electricity resistance may take significantly more (15-20 is not unreasonable), and should be mindful of the risk.

Mechanics

The initial arc strikes the nearest valid target. Each consecutive arc hits every valid target in LOS(including the caster) within three spaces of any victim of the previous arc, unless that target has already been hit. This continues until there are no new targets.

Each arc deals two-thirds the damage of the previous arc. The initial strike deals full damage only at point-blank range, with the damage reduced by one arc's worth from range 2 to 4, and two arcs' worth from range 5 to 7. Half of the spell's damage is irresistible, and only half of the target's AC applies. However, the caster is partially protected, taking only one-sixth damage.

Strategy

• As an area-of-effect spell for taking out many threats (close or far). Chain Lightning works well enough, hitting several nearby targets for decent damage regardless of how they're spaced. It receives its full potential with at least one opponent close to you, and the rest grouped tightly nearby. At moderate spell power, Chain Lightning can take out powerful uniques in 2-3 castings. At maxed out spell power, it becomes one of the most potent damage sources in the game, even partially bypassing electricity resistance.
• Wielding a staff of air provides a significant boost to damage, and grants you resistance to the self-damage; definitely consider wielding one if you can find it.
• Remember that plants, fungi, and bushes are not valid targets for Chain Lightning, so they cannot extend the range of the spell.
• Followers of Beogh, Yredelemnul, or any other character that makes heavy use of allies should use extreme caution before casting Chain Lightning. You are almost guaranteed to injure or kill your allies in the process.

History

• The spell was reworked in 0.27. Prior to this version, Chain Lightning was a Level 8 Conjurations/Air spell that went from target to target, dealing reduced damage each time.
• Chain Lightning was added in 0.1, replacing Orb of Electrocution.