Dessourt is the Dessous of Recipe for Disaster. In the subquest Defeating the Culinaromancer, he is resistant to melee, although strong players may still use melee if they want. He is weak to magic, especially Iban Blast and Wind spells such as Wind Blast . Ranged works well too. A very effective method using melee is wearing full melee void set and a fast weapon. Using Dragon Dagger (p++) special attack is also very effective.
He can be fought in the Nightmare Zone after the quest is complete.
Note: If magic is used to attack him, bring strong melee-resistant armour. He hits hard and fast with melee (around the same speed as throwing rings) and can use magic attacks that hit rapid 5's, similar to his Desert Treasure counterpart. Once a player enters the portal, they should waste no time and head straight for him, unleashing attacks on him.
If you are using magic, you should use a combination of snaring/binding and Iban's blast/wind spells. This will easily take him down with little to no use of food. At high magic levels, it is possible to only have to bind him once or twice.