Marduk Blackpool

Viewing Room
Open the classroom with Rattlegore's key. The students and lecturers begin neutral, so pass without attacking if skipping the classroom event. For the encounters, use Dawn's Gambit from a doorway or corner, clear the transformed students, then engage Marduk before Vectus.

Marduk Blackpool
Elite UndeadMarduk punishes melee attacks into Shadow Shield while Defiling Aura makes the resulting Shadow damage more dangerous.
Abilities

Shadow Shield
Dispel Shadow Shield if possible. It absorbs damage and retaliates against melee attackers, so ranged damage is safer while it remains.

Defiling Aura
Surrounds the caster with an aura that periodically reduces the Shadow resistance of nearby enemies by 100. The aura lasts until cancelled.
Defiling Aura reduces nearby players' Shadow resistance. Keep players who do not need melee range away from Marduk instead of stacking the group around the shield.

Cleave
Keep other melee players away from the tank's immediate position so Cleave does not hit them together.

Shadow Bolt Volley
Hurls missiles of dark magic, inflicting Shadow damage to nearby enemies.
Expect group Shadow damage from the volley, particularly on players who have remained inside Defiling Aura.
Tank- Keep Marduk's Cleave off the group and call for Shadow Shield removal. Holding him away from ranged players limits their exposure to Defiling Aura.
Healer- Use a ranged position rather than sharing Marduk's aura with the tank. Watch melee attackers for shield retaliation and prepare group healing for Shadow Bolt Volley.
Damage- Remove Shadow Shield if your class can dispel enemy magic. Otherwise let ranged damage carry the shield period rather than feeding its retaliation with unnecessary melee attacks.