Normal Duke Sucellus is a preparation stage followed by a melee rhythm: brew two arder-musca poisons, feed them to wake him, attack between slams, hide behind a pillar for his gaze, and change sides when gas targets your position. Protect from Melee reduces chip damage; it does not make a missed slam or gaze safe.
This guide covers the post-quest normal encounter. Current preparation lets you retain resources and prepare several kills in one instance. Awakened Duke requires different preparation and adds hazards that are outside this learner route.
Access and the bank setup
Complete Desert Treasure II. A frozen tablet unlocks the ring of shadows route to Ghorrock Dungeon. Without it, reach Weiss using icy basalt or another working Weiss route, go through the Salt Mine and enter the dungeon. The heavy door leads into the prison near the asylum.
Use a slash melee setup. Emberlight is a useful demonbane option when available; Arclight and ordinary slash weapons are alternatives. Duke’s demonbane vulnerability is reduced compared with many other demons, so do not assume every demonbane bonus applies at full strength. Check charges and actual damage for your equipment.
Bring combat boosts, Prayer restoration, food, an emergency teleport and a good pickaxe for salt. A stamina potion helps if preparation is draining your run energy. Leave several inventory spaces for resources and the pestle and mortar; do not arrive with every slot filled and no plan for temporary space.
A Bandos godsword can help lower Defence in normal mode. Crush-based defence specials are less reliable against Duke’s high crush defence, and Emberlight’s special rolls against stab defence. Choose an appropriate special rather than assume every defence-reduction weapon performs equally.
Stage | Required action |
|---|---|
Gathering | Collect salax salt, arder mushrooms and musca mushrooms |
Grinding | Use a pestle and mortar to produce both powders |
Brewing | Put six of each powder and six salt into each vat |
Waking | Collect and feed two finished poisons |
Combat | Pillar rhythm, gaze cover and gas movement |
Next kill | Use retained supplies or prepare another batch |
Make two poisons safely
The normal recipe needs twelve salax salt, twelve arder powder and twelve musca powder for two poisons in total. Collect the pickaxe and pestle and mortar from the walls if necessary. A better pickaxe improves ordinary salt gathering, while Mining level also affects the quantity gathered.
Mushrooms are at the far ends of the side corridors. Grind them with the pestle and mortar and check the resulting powder stack. At 70 Herblore, each mushroom gives five powder, so three of each type cover one kill; at 80 or higher, two of each type suffice. Count powder rather than assume the same mushroom quantity suits every account.
Avoid the extremities’ gaze in the corridors. It can freeze you, drain Prayer and hit very hard. For a straightforward first preparation, observe when the gaze ends before passing its line. Running routes that skip targeted tiles depend on the exact starting square; do not improvise a diagonal through the corridor.
Watch falling-ice shadows near the stairs and leave the marked tile before impact. In the central salt area, move clear of active gas vents. The preparation can consume food before the combat even starts if you repeatedly tank hazards. Take the time to arrive at the vats in good condition.
Batching changed the preparation routine
Put the required ingredients into both fermentation vats, wait for completion and collect the finished poisons. Heal, restore Prayer and equip the combat weapon before feeding Duke. Do not wake him while still holding the pickaxe or searching for a potion.
Mushrooms and poisons persist between kills in the same instance. Up to eight picks from each mushroom spawn can support preparation for multiple kills, with the practical batch size depending on Herblore. At 80 or higher, a full set of eight picks of each type supports four normal kills.
Leaving the instance removes these preparation resources. Batch only as many kills as your combat supplies can realistically support; extra poisons do not replace food or Prayer. This also means banking ends the value of unused preparation supplies, so collect drops and assess the next kill before deciding to leave.
Build the pillar-and-attack rhythm
Stand directly behind one of the pillars beside Duke when not attacking. This keeps you close enough to encourage melee while avoiding the slam’s direct tile. His raised arms create icicles, followed by a slam. Protect from Melee reduces the icicle damage, but the follow-up slam remains dangerous through Prayer.
Wait for the slam, step out for your attack, then return behind the pillar before the next slam. For initial attempts, accept missed damage opportunities rather than remain exposed for a second hit. Watch Duke’s animation and your own attack cooldown instead of repeatedly clicking as fast as possible.
Staying far away causes a strong magic projectile rather than a safe ranged fight. The pillar method is deliberate close positioning, not hiding anywhere in the room. When changing sides, return to the useful pillar position promptly so Duke does not get repeated opportunities to use magic.
Gaze and gas override your next attack
When Duke opens his eye and the gaze message appears, get directly behind a pillar. Normal gaze gives five ticks before its hit, but can deal lethal damage if you are exposed. Do not stay out for an extra hit until the basic hide is automatic. Resume only after the attack has resolved.
Gas targets the nearby vent. Move to the opposite pillar and keep the route clear of the active cloud. Below half health Duke can send two gas flares, so watch the second target instead of immediately returning to the first side. Keep the eye message in view during the movement.
Gas frequency changes during the fight, so a memorised opening count is not a substitute for the visible spit and floor hazard. A gas mask or Slayer helmet can reduce gas damage, but neither turns a cloud into a useful standing tile or protects you from gaze.
Mistake | Practical correction |
|---|---|
Arrive at combat low on food | Slow down gathering and dodge preparation hazards |
Large hit after ordinary icicles | Return behind the pillar before the slam |
Repeated magic damage | Stay in the close pillar positions |
Gaze death | Hide immediately when the eye/message appears |
Hit after changing sides | Watch for the second gas flare below half health |
Rhythm breaks near the end | Adjust to the faster enrage cycle |
The final quarter is faster
At about 25% health, Duke speeds up from a five-tick to a four-tick cycle. Reuse the same visual response but shorten your time exposed. A five-tick weapon cannot safely preserve the same every-cycle attack rhythm indefinitely; skip an opening when its cooldown would leave you vulnerable.
A four-tick weapon can fit the faster cycle, but swapping weapons is optional in normal mode. Learners can finish by making fewer safe attacks. Keep Prayer and health ready before this point, and prioritise the eye and gas over squeezing a special attack into a bad window.
After the kill, collect drops and check supplies before beginning another preparation. A grave appears by the asylum gates if you die. The initial reclamation discount does not protect Hardcore status. The next useful milestone is a short trip with no missed gazes or slams, followed by more efficient batching once the combat is stable.
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