Guide:The Old Duke strategies

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.

Armor

 * 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.

Accessories

 * The Seraph Tracers or Tarragon Wings can be useful because of their mobility stats.
 * The Absorber can be potent for its healing and speed.
 * Alternatively the Ambrosial Ampoule can be used as a defensive option and to negate the effects of the Poison and Venom debuffs.
 * The Community is a useful accessory for its progressive but powerful scaling stats.
 * Statis' Ninja Belt provides a dash and a chance to dodge attacks, which can help with avoiding contact damage.
 * The Flesh Totem can prove particularily useful against the Old Duke to halve contact damage from its charges.
 * Asgard's Valor provides a dash, extra defense, immunity to knockback, and immunity to several debuffs, particularly the debuffs caused by the Feral Bite debuff.
 * It is also possible to use the Ursa Sergeant to counter the Feral Bite debuff entirely, in such case Elysian Aegis may replace Asgard's Valor.
 * The Reaper Tooth Necklace can be used to boost the damage dealt when The Old Duke is not exhausted.
 * Melee users can use the Fire Gauntlet or Yharim's Insignia for their increases to melee stats along with the Celestial Shell.
 * Ranged users can deal extra damage with the Artemis Emblem and Sniper Scope.
 * Mages should utilize the Sigil of Calamitas and the Mana Flower.
 * Summoners can use Statis' Curse and the Star-Tainted Generator for an increase to minion damage and slots, the Profaned Soul Artifact can also be utilized.
 * Rogues will benefit from the Dark God's Sheath and the Vampiric Talisman.

Melee

 * The Soul Edge and Galileo Gladius are effective homing weapons that can deal great damage and help with focusing on dodging.
 * The Crescent Moon can deal great damage to the Old Duke, especially in its "tired" phase.
 * The Last Mourning, Lion Heart and the Gilded Proboscis are options for true melee damage.

Ranged

 * 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.

Magic

 * 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 and the Stratus Sphere can be used to fry the Old Duke when it is in its "tired" phase.
 * The Thunderstorm (RIV) can be extremely viable thanks to its damage output, however it may be difficult to obtain due to its rarity.
 * The Phantasmal Fury can also be used as a viable option, due to the homing capability of the trailing bolts and large damage output.

Summoner

 * The Ethereal Subjugator and Sirius can work in conjunction by using half of a player's minion slots each.
 * The Calamari's Lament can also be utilized with full slots.
 * The Gamma Heart is also useful, especially with the Gamma Deathray attack.

Rogue

 * The Time Bolt can be a powerful weapon if its copies can also land hits.
 * Night's Gaze can be potent for damage.
 * The Valediction is an excellent homing weapon.
 * The Reaper (RIV) is even more powerful, however it may be difficult to obtain due to its rarity.

Miscellaneous

 * The Well Fed buff provides a useful all around stat boost.

Phase 1
Once the Old Duke has been summoned, the fight will begin in its first phase unless Death Mode is active, throughout the fight 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 significantly reduced defense and 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.
 * 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.
 * Charges three times again.
 * Pulses and summons two groups of vulnerable Sulphurous Sharkrons left and right of itself, these sharkrons inflict the Venom, Poisoned, Irradiated, and Feral Bite debuffs upon contact damage for three seconds, they will also explode into two damaging Sulphurous Gore chunks when killed or making contact with tiles, these inflict the Poisoned and Irradiated debuffs 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 and dashing after the Old Duke charges can help greatly when avoiding them.

Phase 2
If Death Mode is active, this is the first phase of the fight, otherwise after the Old Duke is reduced to 50% of its health in Normal Mode and 70% in Expert Mode, it will transition to this phase, the transition is indicated when 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 spit out five Tooth Balls and form 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. 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.

Phase 3
Once deprived to 20% of its health in Expert Mode, 35% in Revengeance Mode, and 50% in Death Mode, the Old Duke will start to become more translucent and green, becoming invulnerable for its first two attacks, 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 gains the ability to teleport to a location near a player before it begins its charging attacks, these teleports do not count towards the Old Duke losing stamina. The Old Duke will additionally charge three times before summoning the Sulphurous Vortex instead of twice.

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.

General Tips

 * 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.
 * 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.