Great Magic Weapon is a Sorcery in Dark Souls 2. To cast a Sorcery, you must use a Staff or Special Weapons that can cast Sorcery.
Great Magic Weapon
"A sorcery superior to Magic Weapon. Reinforces weapon in other hand with intense magic, allowing for infliction of heavy magic damage.
The old purists of the Melfian Magic Academy view swordplay as a barbaric form of engagement."
- Company of Champions Rank 1 reward.
- Purchased from Royal Sorcerer Navlaan by 6000 souls.
- Found in a iron chest in Black Gulch.
- Buffs weapon with magic damage. Duration scales with Intelligence: 65 sec. at 18 Int, and up to 108 sec. at 27 Int. Superior to Magic Weapon, but inferior to Crystal Magic Weapon. Equivalent to Flame Weapon in effectiveness.
- The duration is directly related to intelligence. If you use Simpleton's Spice to reduce the cost to 10, the spell will only last roughly 20 seconds.
- The duration also ends immediately if you switch the enchanted weapon out.
- Rather unsurprisingly, this cannot be used to buff any magical catalysts like a staff (if you wielded two staffs and enchanted with the offhand one), so a Sorcerer cannot self-buff their spells with it. The exception to this are catalyst-weapons, like the Blue Flame
- DS2's buff formula differs from other Souls games, instead relying primarily on the targeted weapon's base damage to determine how much AR the spell buff will add. Matching the spell buff with a damage type present on a weapon will add a flat bonus to the total AR, depending on whatever the weapon is infused with and/or naturally inflicts said damage type. A small scaling bonus is also added, unless the targeted weapon doesn't scale at all with any stats.