Stormguild is a unique Large Shield from Diablo II: Lord of Destruction.
With very high chances of blocking, Stormguild will give close to max probability of blocking hits even with a Druid, Necromancer, or Sorceress. Paladins, of course, can use Stormguild even more effectively.
Stormguild is a low level item, and is generally most useful in early game (particularly in Normal difficulty). Its Lightning Resist may be particularly useful in early game against Death Beetles found in Act II, or Lightning Enchanted bosses.
As an added bonus, Stormguild adds an amount of Lightning damage to attacks. Although the amount is miniscule at best, it can be useful in very early game when any added damage helps.
Still, because Stormguild is a low level item, it will most likely be replaced by other, more powerful shields in later levels, particularly since Stormguild doesn't add diverse Resistances.
Stats[]

Stormguild
Large Shield
Defense: 52-54
Required Level: 13
Required Strength: 34
Durability: 34-39
Chance to Block:
Paladin Smite Damage: 2 To 4
+50-60% Enhanced Defense
+30 Defense
+30% Increased Chance to Block
Lightning Resist +25%
Adds 1-6 Lightning Damage
Attacker Takes Lightning Damage Of 3
Magic Damage Reduced By 1
Normal Shields — Pelta Lunata (Buckler) • Umbral Disk (Small Shield) • Stormguild (Large Shield) • Steelclash (Kite Shield) • Swordback Hold (Spiked Shield) • Bverrit Keep (Tower Shield) • Wall of the Eyeless (Bone Shield) • The Ward (Gothic Shield)
Exceptional Shields — Visceratuant (Defender) • Moser's Blessed Circle (Round Shield) • Stormchaser (Scutum) • Tiamat's Rebuke (Dragon Shield) • Lance Guard (Barbed Shield) • Gerke's Sanctuary (Pavise) • Lidless Wall (Grim Shield) • Radament's Sphere (Ancient Shield)
Elite Shields — Blackoak Shield (Luna) • Stormshield (Monarch) • Spike Thorn (Blade Barrier) • Medusa's Gaze (Aegis) • Head Hunter's Glory (Troll Nest) • Spirit Ward (Ward)