Guide:The Old Duke strategies

From Calamity Mod Wiki
Jump to navigation Jump to search
The Old Duke
The Old Duke.png
The Old Duke
Map icon
EnvironmentSulphurous Sea
DamageThis attack will cause defense damage on hit. 160 / 288 Expert Mode / 324 Revengeance Mode / 342 Death Mode / 432 Master Mode (Contact in Phase 1)
This attack will cause defense damage on hit. 176 / 316 Expert Mode / 356 Revengeance Mode / 376 Death Mode / 475 Master Mode (Contact in Phase 2)
This attack will cause defense damage on hit. 192 / 345 Expert Mode / 388 Revengeance Mode / 410 Death Mode / 510 Master Mode (Contact in Phase 3)
170 / 296 Expert Mode / 324 Revengeance Mode / 340 Death Mode / 462 Master Mode (Gore)
This attack will cause defense damage on hit. 280 / 400 Expert Mode / 440 Revengeance Mode / 464 Death Mode / 660 Master Mode (Vortex)
Max Life500,000 / 800,000 Expert Mode / 960,000 Revengeance Mode / 1,200,000 Master Mode / 1,440,000 Revengeance Mode Master Mode
Defense90 (attacking in Phase 1)
70 (attacking in Phase 2)
50 (attacking in Phase 3)
0 (exhausted)
DR50% (attacking)
0% (exhausted)
KB Resist100%
Inflicts debuffIrradiatedIrradiated
100% chance

Debuff duration10 seconds (Vortex)
8 seconds (Contact)
3 seconds (Gore)
Debuff tooltipYour skin is burning off
Immune toConfusedPoisonedAcid VenomPearl AuraSulphuric PoisoningIrradiated
Cold Bestiary Cold.png-
Water Bestiary Water.pngResistant
Sickness Bestiary Sickness.pngResistant
Electricity Bestiary Electricity.pngVulnerable
Heat Bestiary Heat.pngResistant

The Old Duke is a post-Moon Lord boss than can be fought in the Sulphurous Sea biome after defeating Polterghast. It is summoned by finishing the third tier of the Acid Rain event or by fishing with Bloodworms in the Sulphurous Sea.

This guide will mention Expert Mode and Revengeance Mode exclusive accessories with no special formatting and will follow the intended progression.

Terrain Preparation

A large open area with either 3 layers of platforms 40-50 blocks apart or several rows of stacked Minecart Tracks 30 blocks apart can help with dodging several of the Old Duke's attacks.

Gearing Up


  • Bloodflare armor is the preferred choice for all classes in this stage of the game.
  • Omega Blue armor may also be utilized because of its immense offensive stats, but severely lacks at defensive stats in turn.
  • Tarragon armor can be viable, but is considerably low tier for the current stage of progression.





  • Dodu's Handcannon can deal great damage to the Old Duke at the cost of having to aim.
  • The Handheld Tank can tear through the Old Duke's "tired" phase with the Bloodflare armor bonus.
  • The Monsoon can deal tremendous amounts of damage with its fast use time when paired with Elysian Arrows.
  • The Daemon's Flame is another bow option that does respectable damage.
  • The Sulphuric Acid Cannon does dependable high DPS without the need to aim.


  • The Ghastly Visage is a great homing weapon that can allow focusing on dodging.
  • The Shadowbolt Staff and Viscera can prove effective with walls while the Viscera can also provide lifesteal.
  • Clamor Noctus can be used to fry the Old Duke when it is in its "tired" phase.
  • The Phantasmal Fury can also be used as a viable option, due to the homing capability of the trailing bolts and large damage output.



  • The Time Bolt can be a powerful weapon if its copies can also land hits.
  • The Night's Gaze can be potent for damage.
  • The Valediction is an excellent homing weapon.


The Fight

Phase 1

Once the Old Duke has been summoned, the fight will begin in its first phase. Throughout the fight after every ten attacks the Old Duke performs it will lose stamina, become "exhausted" and pause for 5 seconds, making a "huffing" sound as it does this. Rage and Adrenaline should be saved for when the Old Duke does this as it will have no defense or DR. In the first phase the Old Duke follows a set attack pattern, repeating in this order:

  • Charges three times with brief breaks in between them, with the Old Duke's charge direction taking a player's velocity into account, attempting to head for their predicted destination, these charges occur faster and with more velocity in Revengeance Mode and Death Mode. Take care in carefully dodging these to avoid massive damage. Dashing after the Old Duke charges can also help greatly when avoiding them.
  • Spits 5 invincible Tooth Balls that target players for 8 seconds, before becoming stationary and vulnerable after 10 more seconds, killing, making contact, or letting these Tooth Balls live for 15 seconds will cause them to explode into 4 or 8 homing teeth in an outward cross formation, along with spawning a remaining sulphur cloud where the initial explosion took place. Tooth Balls move quickly but have trouble turning around, so they can be dodged by quickly turning a different direction on them.
  • Charges three times, again taking player velocity into account.
  • Pulses and summons two groups of vulnerable Sulphurous Sharkrons left and right of itself. These Sharkrons inflict the Irradiated debuff upon contact damage for four seconds. They will also explode into two damaging Sulphurous Gore chunks when killed or making contact with tiles, which inflict the Irradiated debuff for three seconds.

Players can generally fly around the area and drop down far away from the Old Duke to avoid most of its attacks, grappling onto Minecart tracks can provide extra mobility for outrunning the Old Duke.

Phase 2

After the Old Duke is reduced to 50% / 70% Revengeance Mode / 80% Death Mode of its health, it will transition to this phase, as the Old Duke becomes invulnerable and visibly gains yellow glowing eyes, it will fire 6 Sulphurous Sharkrons upwards as it does this and goes on a modified attack pattern that also repeats itself:

  • The Old Duke will now only charge twice, however these charges are faster and still take velocity into account.
  • It will fly in a circle, spitting out five Tooth Balls and forming a Sulphurous Vortex that will draw players around and into it if close enough, these linger around for 30 seconds until vanishing.
  • The Old Duke will charge twice again.
  • It will summon two groups of five Sulphurous Sharkrons and vomit a large amount of gravity-affected Sulphurous gore chunks.

Players can still fly around the area and drop down far away to avoid most of these attacks, but it might become necessary to dodge the Old Duke's charges a lot more as it may catch up to players easier. Remember that the Old Duke will still become tired after every ten attacks, so saving burst damage for these is recommended. Avoiding the vortexes the Old Duke spawns can be a nuisance when they take up space in the area so avoiding them entirely should be prioritized. Alternatively, you can try to lure the Old Duke into a corner when he is going to spawn the vortex, so that it is out of the way.

Phase 3

Once reduced to 20% Expert Mode / 35% Revengeance Mode / 50% Death Mode of its health, the Old Duke will start to become more translucent and green, becoming invulnerable for its first two charges and a Sulphurous Sharkron attack. After its first initial teleportation, it becomes vulnerable again.

The attack pattern it follows is the exact same as phase 2, however its charges are even faster, it will charge three times before summoning the Sulphurous Vortex instead of twice, and it gains the ability to teleport to a location near a player before it begins its charging attacks, which do not count towards the Old Duke losing stamina.

Priority should now be on avoiding the Old Duke's charges at all costs as its teleport ability allows it to catch up to players significantly, dashing out of the way after the Old Duke charges or grappling onto Minecart tracks for extra mobility are still extremely helpful for this phase. It is also useful to being falling when the Old Duke does teleports and charges, and he will always teleport above you.

General Tips

  • Some of the Old Duke's behavior is reminiscent of Duke Fishron. As such, it may be beneficial to study Duke Fishron's attack pattern beforehand.
  • It is most optimal to be positioned above or below the Old Duke at all times, as dodging its charges is significantly more difficult in a horizontal alignment.
  • Try to avoid the Tooth Balls at all costs, as they can sometimes damage you several times at once, and potentially lead to an unexpectedly quick death.
  • Bloodfins are an effective healing item for this boss.
  • The Rod of Discord or the Normality Relocator are useful tools for avoiding the Old Duke's attacks.
  • The Bobbit Hook is extremely good for mobility because of its fast retraction time and launch speed.