The Demon Plate has higher Armor Class against Demons, making it more useful against virtually all the monsters you see in the Hell levels leading up to Diablo.
Due to a bug in the item generation mechanism, this is the only Unique Full Plate Mail which can be found in Multiplayer Hellfire.
It is notable that its extra-armor attribute gives it only 5 more to its base Armor Class.
Demon Plate bears similar resemblance in aspect of design style to the Unique Helm, Overlord's Helm.
Stats[]

Demon Plate
Full Plate Mail
- Armor Class: 80
- Extra 120 Armor Class vs Demons
- Requirements: 90 Strength
- Durability: 90
- Quality level: 25
- Availability: Single Player and Multiplayer, Hellfire only
Diablo I Unique Body Armor — Torn Flesh of Souls (Rags) • Nightscape (Cape) • The Rainbow Cloak (Cloak) • Wisdom's Wrap (Robe) • Leather of Aut (Leather Armor) • The Gladiator's Bane (Studded Leather Armor) • Arkaine's Valor (Ring Mail) • Scavenger Carapace (Breast Plate) • Sparking Mail (Chain Mail) • Naj's Light Plate (Plate Mail) • Demonspike Coat (Full Plate Mail)
Hellfire Unique Body Armor — Bone Chain (Chain Mail) • Bovine Plate (Plate Mail) • Demon Plate (Full Plate Mail) • Armor of Gloom (Full Plate Mail)