CM
Adventurer
As others have mentioned, Nagpa are probably the closest. I got a lot of mileage out of 4e Nagpa Corruptors reskinned as generic enemy spellcasters:
Withering Staff (necrotic, weapon) At-Will
Attack: Melee 1 (one creature); +13 vs. Reflex
Hit: 2d6 + 10 necrotic damage, and the nagpa pushes the target 2 squares.
Withering Blast (implement, necrotic) At-Will
Attack: Ranged 5 (one creature); +13 vs. Will
Hit: 2d8 + 4 necrotic damage, and the target is immobilized (save ends).
Devouring Fire (implement, fire) Recharge
Attack: Ranged 5 (one creature); +13 vs. Fortitude
Hit: 2d10 + 10 fire damage, and ongoing 5 fire damage (save ends).
Each Failed Saving Throw: Each ally within 3 squares of the target takes 5 fire damage.
Corrupting Curse (necrotic, zone) Encounter
Attack: Area burst 3 within 10 (enemies in the burst); +13 vs. Fortitude
Hit: 2d6 + 5 necrotic damage.
Effect: The burst creates a zone that lasts until the end of the encounter. Any enemy within the zone cannot regain hit points.
Attack: Melee 1 (one creature); +13 vs. Reflex
Hit: 2d6 + 10 necrotic damage, and the nagpa pushes the target 2 squares.
Withering Blast (implement, necrotic) At-Will
Attack: Ranged 5 (one creature); +13 vs. Will
Hit: 2d8 + 4 necrotic damage, and the target is immobilized (save ends).
Devouring Fire (implement, fire) Recharge
Attack: Ranged 5 (one creature); +13 vs. Fortitude
Hit: 2d10 + 10 fire damage, and ongoing 5 fire damage (save ends).
Each Failed Saving Throw: Each ally within 3 squares of the target takes 5 fire damage.
Corrupting Curse (necrotic, zone) Encounter
Attack: Area burst 3 within 10 (enemies in the burst); +13 vs. Fortitude
Hit: 2d6 + 5 necrotic damage.
Effect: The burst creates a zone that lasts until the end of the encounter. Any enemy within the zone cannot regain hit points.