Acid Ball/Rain of Sorrow
School Arcane
Type Damage
Range Ball
Base cost 35
Equivalent item N/A

Acid Ball is an arcane offensive spell in ADOM. It allows the caster summon an acidic cloud around himself/herself, damaging all beings in the area.

Acid Ball is the most expensive (and powerful) ball spell in the game, thus sharing the following common features:

  • Effective range is approximately a circle (counting in tiles) with the radius based on the PC's Willpower
  • Attacking monsters with Acid Ball while invisible will betray the PC's location to them
  • Acid Ball will damage everything in its effective area including monsters in walls and outside the PC's line of sight

There are no enemies in the game which are vulnerable to acid-based attacks, but there are also few enemies in the game which are resistant to acid-based attacks. Moreover, these monsters do not include the majority of game bosses. This fact, combined with Acid Ball's superior damage, makes it the top offensive spell in the game. A lot of players consider spellbooks of Acid Ball worthy of spending a wish.



Acid Ball damage is dependent mainly on the PC's level (L) and slightly on spell proficiency (P). The exact formula is the following:

max{3, [2 + L / 4]}d9 + L + P


Acid Ball radius is solely dependent on the PC's Willpower (W). The exact formula is the following:

max{2, [W / 8]}

Only every even value signifies a different blast size. Radius value should be divided by 2 and rounded down — the resulting number corresponds to actual circle radius counting in level tiles. In practice, an observable increase in spell radius will first occur when the PC reaches a Willpower score of 32. Every 16 more points of Willpower (48, 64, etc.) will trigger another increase.

Ball spell radius 2, 3 (1-31 points of Willpower)
Ball spell radius 4, 5 (32-47 points of Willpower)
Ball spell radius 6, 7 (48-63 points of Willpower)


Acid Ball will destroy items on the floor, herbs, and webs.

Some information taken with permission from Andy Williams' Guidebook.

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