Bone Spirit

Releases a spirit of the restless undead that tracks its target or finds one of its own.

Bone Spirit is the level 30 Necromancer spell at the end of the Poison and Bone tree's bone branch (requires Bone Spear; it unlocks nothing). It fires a single homing missile that deals magic damage to one target: 20–30 at level 1, 340–369 at level 20, before its four synergies at +8% per hard point. Where Bone Spear pierces a line, the spirit seeks one target within a 10-yard search radius and passes through everything else to reach it. Mana is 12 at level 1 and 21.5 at level 20.

The numbers

• Magic damage is EMin 20 to EMax 30, with five brackets that climb by one each: the minimum grows +16 a level to level 8, +17 to 16, +18 to 22, +19 to 28 and +20 past that (EMinLev1–5); the maximum grows +17 to 8, +18 to 16, +19 to 22, +20 to 28 and +21 past that (EMaxLev1–5). That gives 20–30 at level 1, 166–185 at level 10, 340–369 at level 20, 530–569 at level 30. The growth is almost linear, so a level is worth about the same at level 5 as at level 25.
• Mana is 24 hundred-and-twenty-eighths plus 1 a level (mana 24, lvlmana 1, manshift 7): 12 at level 1, +0.5 a level, 21.5 at level 20, 26.5 at level 30. The Basin writes it as 11.5 + 0.5 × level.

Both lines read the full skill level, so +skills count. The synergy reads hard points only (blvl).

How it works

Bone Spirit is a missile cast (srvmissilea "bonespirit"): no attack roll, no weapon damage, no leech, Crushing Blow or Open Wounds. Its casting speed is set by Casting Speed and faster cast rate. The damage is magic (EType "mag"), read against the target's magic resistance (Dealing Elemental Damage). The Basin's rules for how it finds a target:

• It seeks a target within its 10-yard search radius and tracks it, re-checking the target's position every 5 frames (the targeting interval), as long as the target stays within the radius.
• The target must be in the player's line of sight: the spirit cannot target a monster around a corner even inside the radius, and if the target moves behind an obstacle the spirit does not go around it.
• When a selected target dies, the player stops firing, and any spirit already in flight carries on in a straight line without hitting anything. If the selected target moves out of range, the player keeps firing but the spirits do not hit.
• With no target selected, the spirit picks one within its search radius when it reaches its destination. A Unique monster is normally chosen before its minions, even when the minions are closer. If nothing is in the radius it flies straight on and hits anything in its path.
• It passes through every unit between the player and the target without hitting anything but the target.

The spirit is one hit on one target. Against a pack it is the Bone Spear's price again for a single kill; its place is the boss, the Unique it homes on first, and the target you cannot line up.

Synergies and +skills

The synergy is EDmgSymPerCalc (Bone Wall.blvl + Bone Prison.blvl + Teeth.blvl + Bone Spear.blvl) × par8, Param8 8, printed as four tooltip lines:

• Teeth: +8% Magic Damage per Level
• Bone Wall: +8% Magic Damage per Level
• Bone Spear: +8% Magic Damage per Level
• Bone Prison: +8% Magic Damage per Level

All four read blvl, hard points only. The Basin notes the older value was 6% a level in Lord of Destruction and 8% in Resurrected; the table's 8 is the current game. Bone Spirit in turn feeds Teeth and Bone Spear by hard points, as their pages show. Items with +% Magic Skill Damage apply as the stat page describes. No mastery raises it.

Against players

A player's hit on another player is cut to 17% of its value (difficultylevels.txt PlayerDamagePercentVSPlayer) before anything else; the magic damage is then read against the player's magic resistance. The spirit's homing works as above. The Basin's page records no other player-versus-player rule for this skill. See Player versus Player.

Build notes

• Level 20 is 340–369 for 21.5 mana, about 1.8 times Bone Spear's level 20 damage for about 1.8 times the mana; every +1 past that is worth +19 to +21 damage.
• The same four-skill synergy pool as Bone Spear, at the same +8% a point, feeds both: a bone caster who maxes Teeth, Bone Wall, Bone Prison and one of the two missiles has +640% on the other.
• Hard points in Bone Spirit feed Bone Spear and Teeth; +skills from items raise its own damage but feed nothing.