Duke Sucellus

Duke Sucellus is the fourth of the Forgotten Four, and the only one of them you cannot simply walk in and hit. He is asleep when you arrive, and waking him is a job of work you do inside his own asylum, with ingredients that only exist in there.

::duke and the Bosses teleport row both open a fresh copy of the asylum, instanced per run, so nobody can crash your kill. The same command takes you back out.

Bring 20 slots, not 28

The single most important thing about this fight. Waking Duke takes a chain of items you farm, grind and ferment on the spot, and it peaks at six held slots. A player who arrives with a full inventory cannot pick the first mushroom, which means they cannot start the boss they came for. Leave at least six slots free, and expect to spend most of the other twenty on the fight itself - this is a one-kill-per-trip boss, so there is no point hoarding.

Everything you farm in there is stripped from your inventory when you leave. There is no stockpiling the poison between runs.

Waking him up

Duke tolerates 200 points of poison and each dose is worth 100, so you need two doses. One dose is:

1. Six arder mushrooms and six musca mushrooms, picked from the patches at the far end of each side corridor.
2. Six salax salt, mined from the salt deposits. You need a pickaxe - there is a free one on the wall by the entrance if you did not bring your own.
3. Grind the mushrooms at the pestle and mortar. Herblore decides the yield: one powder per mushroom at level 30, up to six each at level 80, so a high Herblore level is the difference between two trips down the corridor and one.
4. Fill a vat with 6 arder powder, 6 musca powder and 6 salax salt, wait for it to ferment, then collect the dose. There are two vats, so both doses can ferment at once.

Then use each dose on the sleeping Duke. The second one wakes him.

The corridors are the dangerous part

The two side corridors are not a safe walk, and this is where most of the damage on a clean trip comes from.

Falling icicles drop on random corridor tiles with a moment's warning shadow. One landing on you hits for up to 18 and roots you for a couple of ticks. They are unavoidable in the sense that you cannot clear the corridor of them - but they are telegraphed, and the tiles you actually stand on to pick each mushroom are permanently safe.

The extremities - the growths down each side - wake in sequence and sweep a gaze across the corridor. Getting caught costs up to 70, freezes you for five ticks and drains a quarter of your prayer. This one is avoidable: the three on each side fire on a fixed twenty-tick cycle, so setting off just after the southernmost one has fired walks you the whole way through the gap between beams. Time it and you take none of them.

The fight

Duke is a 7x7 mound with 485 hitpoints, 275 defence and a crush-shaped defence profile: 255 against stab, 190 against crush and only 45 against slash. Slash is the answer, and it is not close.

His normal attacks come every 5 ticks, dropping to every 4 below 25% health:

• Melee when you are beside him: an icicle jab, then a slam for up to 56, or 42 through Protect from Melee. The slam is the single biggest thing he does with an ordinary attack.
• Magic when you are not: an ice blast for up to 48.

Two specials sit on top of that:

Freezing Gaze. He announces it, charges for five ticks and then resolves for 50 to 101 damage and a three-tick freeze. That is a quarter of most health bars in one hit, and it is the attack that kills people who are not paying attention. The four tiles just past each end of him are out of his line of sight and the gaze misses entirely - but they are also on his diagonal or past it, so you cannot hit him from there. It is cover, not a camping spot.

Gas Flare. He spits at the vents in the middle of the chamber and they erupt for up to 12 each, within one tile. A slayer helmet or a gas mask halves it. The flare always arrives three standard attacks after a gaze, and then on a cadence that tightens as his health drops: every five attacks above 75%, every four in the middle, every three once he is enraged below 25%.

What to bring

Protect from Melee and a slash weapon, and stay potted - a super combat is worth roughly a third of the kill time here, which is more than the brews it costs you.

Do not count on an Arclight. Duke is the one demon in the game that *resists* demonbane rather than amplifying it: his resistance is 70%, so an Arclight or Emberlight is worth +49% against him instead of the usual +70%. He is also immune to both poison and venom.

Rewards

The Magus vestige is his headline unique, and the first half of the Magus ring: vestige plus an imbued Seers ring plus 500 blood runes makes the icon, and the icon plus three chromium ingots makes the ring. The Eye of the Duke is his quarter of the Soulreaper axe - one piece from each of the Forgotten Four. The Ice quartz for the ancient sceptre comes off the same table, along with the chromium ingots all four rings need, and a share of Virtus.

Upgrades has the full recipes.