The Spire of Lazarus primarily provides nice bonuses to Lightning Spells. Over all, it gives the highest boost to Static Field, one of the Sorceress' most useful spells. However, levels into Static Field only increase the radius of its effect, so levels into it are sometimes interpreted as unnecessary.
Even though the Spire of Lazarus gives specific bonuses to Lightning Spells, in later game, its skill bonuses are easily overshadowed by other items including Chromatic Ire or Mang Song's Lesson. Most Sorceresses that specialize in Lightning Spells (most commonly Chain Lightning) often opt for other staves, or even Unique Orbs such as The Oculus.
However, the Spire of Lazarus offers other bonuses that are worth mentioning and utilizing as well. It gives a very large boost to Mana regeneration, which, when combined with the effects of Warmth or other items such as Manald Heal, can give a Sorceress amazing mana regeneration, giving her effectively unlimited potential for casting spell after spell without a need for Mana Potions.
Appropriately, Spire of Lazarus may ignore other resistances, but gives a large boost to Lightning Resist. A character that takes advantage of this resistance, and compounds it with the effects of armors such as Thundergod's Vigor or other lightning resistant equipment, can become almost completely immune to Lightning Damage even as late as Hell mode.
Spire of Lazarus
Two-Hand Damage: 4 To 12
Required Level: 18
Staff class - Slow Attack Speed
+50% Damage To Undead
Adds 1-28 Lightning Damage
+1 To Sorceress Skill Levels
+2 To Lightning (Sorceress Only)
+1 To Chain Lightning (Sorceress Only)
+3 To Static Field (Sorceress Only)
Regenerate Mana 43%
+15 To Energy
Damage Reduced By 5
Lightning Resist +75%
- The staff may be named in reference to Archbishop Lazarus.