TL;DR: The Dark Crystal (DC) Robe Set is an A-grade robe built around M.Atk and MP. It's the offensive alternative to the Majestic Robe โ€” best for nukers who want maximum spell damage over survivability.

Overview

The Dark Crystal Robe Set is an A-grade robe set focused on magic attack and MP. It's the offensive counterpart to the Majestic Robe: pick it when you'd rather deal damage than play safe. The pieces drop Sealed, so you'll need to unseal them at the Blacksmith of Mammon for Ancient Adena before you can fully enchant or transfer them.

Set Bonus

Wearing the full DC Robe Set boosts your M.Atk and increases your maximum MP. That makes it an ideal choice for nukers who care about top-end spell damage, while the extra MP lets you farm longer between mana breaks.

BonusEffect
M.AtkHigher magic attack โ€” a direct multiplier on every nuke.
Max MPLarger mana pool, so you stay in your casting rotation longer without downtime.
UnsealingAll pieces start Sealed; unseal at the Blacksmith of Mammon for Ancient Adena.

DC vs Majestic Robe

The DC Robe gives more M.Atk but less defense and HP than the Majestic Robe. For PvE farming the DC Robe is more efficient โ€” you kill mobs faster. For PvP and the Olympiad the Majestic Robe is the safer pick, since its HP and casting-speed bonus help you survive.

Robe SetStrengthBest for
Dark CrystalHigher M.Atk, more MPPvE farming; Spellhowler and Necromancer (damage)
MajesticMore HP, casting speedPvP and Olympiad; Bishop and Sorcerer (versatility)

Recommendation: take the DC Robe for damage-oriented mages, and the Majestic Robe when you value survivability and all-round utility.