Guide:Astrum Deus strategies

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Astrum Deus
Astrum Deus.png
Astrum Deus
Map icon
TypeBossBurrowing Enemy
EnvironmentAstral Infection
Max Life600,000 / 960,000 Expert Mode / 1,152,000 Revengeance Mode / 1,440,000 Master Mode / 1,728,000 Revengeance Mode Master Mode (total)
KB Resist100%
Inflicts debuffExtreme GravityExtreme Gravity
100% Revengeance Mode chance

Debuff durationInfinite
Debuff tooltipYour wing time is reduced by 25%, infinite flight is disabled
Cold Bestiary Cold.png-
Water Bestiary Water.png-
Sickness Bestiary Sickness.pngResistant
Electricity Bestiary Electricity.png-
Heat Bestiary Heat.pngVulnerable

Astrum Deus is a late Hardmode boss that can be fought after the Lunatic Cultist in order to gain access to Astral Ore. Astrum Deus is summoned by using a Titan Heart on an Astral Beacon at night. For future battles after the first defeat, Astrum Deus may be summoned using a Starcore on an Astral Beacon at night instead.

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

Terrain Preparation

Astrum Deus is not bound to any biome and will not enrage due to biome restrictions. As Astrum Deus requires a lot of space, it is important to cover up holes in the ground to prevent yourself from getting caught by uneven terrain. Generally, a large open space with several platforms is adequate.

For a dedicated arena, flatten out the surface of a biome (or an area that's about 800 to 1000 blocks long). You'll need 3,000+ platforms for this, so get those first. Place four layers of platforms, each spaced at least fifty blocks apart from the nearest block/platform. This will give you plenty of vertical and horizontal space to fight the boss.

Additionally, killing a few of the Celestial Pillars will minimize interruptions during the fight.

Gearing Up




Weapons made from the Lunar Fragments are typically your best options.


  • The Tenebreus Tides performs exceptionally well due to its high damage and piercing.
  • The Aegis Blade is a very strong true melee weapon that deals very high DPS to Astrum Deus.
  • The Hydraulic Volt Crasher can deal extreme damage to Astrum Deus, especially with adrenaline. It can bring the boss to its second phase with one cycle of adrenaline and bring one of the worms to extremely low HP, or potentially even kill the boss, with a second cycle. However, its range is incredibly short.
  • The Grand Guardian performs well with large explosions on every hit.
  • The Daybreak is a strong, safe option that can do large amounts of damage to Astrum Deus with its explosions.
  • The Solar Eruption's piercing will do high damage against Astrum Deus, especially when hitting many worms at once. However, its low range can make it risky to use.
  • The Entropic Claymore is a powerful sword that can deal high piercing damage with its homing plasma balls.
  • The Storm Ruler can also be used, although it requires good positioning, despite Astrum Deus only taking half damage from this weapon.


  • The Scorpio performs phenomenally with alternate fire with a massive area of effect. Its homing capabilities make the fight very straight-forward as well.
  • The Gauss Rifle works very well together with Plague Reaper armor, plus Adrenaline if the player is playing on Revengeance Mode or higher.
  • The Dead Sun's Wind performs very well for the boss' first phase with its high piercing allowing it to deal significant damage to many segments at once. Though, this weapon falls a bit off at the boss' second phase due to the shorter and faster worms, especially when they're not often grouped together.
  • The Phantasm with Holy Arrows is an excellent choice due to their piercing.
  • The Vortexpopper deals high damage, and if paired with Chlorophyte Bullets, will rarely miss a shot, allowing the player to focus on dodging Deus's attacks.


  • The Lazhar is an extremely powerful weapon that allows you to decimate Astrum Deus very swiftly, in some cases even under a minute.
  • The Tome of Fates is similar to the Solar Eruption. It has good damage at the cost of being quite dangerously close to the worms.
  • While from a lower tier, the Plague Staff still does surprisingly well against this boss.
  • The Hematemesis, although it can't pierce, is a good option as all of the projectiles from its wide attack will likely hit.
  • The Cosmic Rainbow is a powerful option that can be awkward to use but does well as the worms are falling back to the ground.
  • The Charged Blaster Cannon's full beam is ridiculously powerful on Deus, easily dealing upwards of 100,000 damage per second in phase 1 if you line up a worm with the beam, or 50,000 DPS in phase 2, even without adrenaline, and has extreme range.
  • The Atlantis can decimate large chunks of health if aligned properly, thanks to its multi-hit and piercing capabilities.


  • The Terraprisma is an incredibly powerful option, with the blades dealing high damage and attacking multiple segments quickly.
  • The Stardust Dragon Staff is a very good option, as it can pierce the many segments of Astrum Deus.
  • The Spikecrag Staff is an excellent option with its wide area of effect being able to take advantage of Astrum Deus' large hitboxes.
  • The Kaleidoscope is the best whip obtainable and should be used as support.
  • The Desert Tiger Staff can kill multiple phases of the boss in seconds if spammed at close range.


  • The Deep Wounder's stealth strike does unbelievable damage to Astrum Deus when lined up correctly, due to its high damage and infinite pierce. It also has incredible synergy with the Dark Matter Sheath.
  • The Star of Destruction can pierce the boss if used properly and should definitely be utilized.
  • The Malachite can deal very high damage with its explosions.
  • The Cranium Smasher is a great option for Rogue users with good piercing and DPS.
  • The System Bane can provide some passive DPS as a side weapon.
  • The Duststorm in a Bottle can provide good piercing and DPS and is best for Phase 1, despite being early Post-Plantera.


  • Yanmei's Knife is an extremely powerful weapon which is made most effective right when Astrum Deus spawns, due to its debuff dealing 125 damage per second, so multiple segments can be inflicted with it. It should be treated as more than a side-weapon in this fight.


The Fight

Phase 1

Upon being summoned, Astrum Deus will take little damage until a few seconds have passed. Astrum Deus has a few different attacks in this phase:

  • Fires lasers from each segment of its body, one by one. This attack happens every 10 seconds.
    • The rate of fire of the lasers staggers as Astrum Deus's health decreases, making the attack longer.
  • Burrows through the ground, after which it attempts to ram the player from below.

After reaching 80% of its health, Astrum Deus will alternate between burrowing and flying every 15 seconds, leaving behind mines near tail when flying. At 70% and below, some mines can explode into an X of lasers, with the chance of exploding increasing as its health decreases.

The lasers can be dodged by constantly maneuvering around Astrum Deus, while the mines released should be kept at a distance or have their placements memorized to help with staying away from them. Memorizing the mines positions also helps with dodging the lasers the mines can explode into, as they can only move in the X shape, thus leaving the cardinal directions safe for travel. Astrum Deus's rams may be avoided by simply jumping or dashing out of the way, however it should be noted that the boss' projectiles may occasionally get in the way, whether it be left over mines or lasers directly fired afterwards.

Phase 2

Once Astrum Deus is below 50% of its health, it will split in half and the fight will be composed of 2 worms. One of the worms will start off burrowing and will be colored orange, while the other one will start off flying and will be colored blue. This is the most difficult section of the fight, as while each worm still goes with the original worm's AI, both of them act separately and are considerably faster, meaning it is much more difficult to avoid attacks from one worm without being intercepted by the other. It should be noted however, that in most difficulties only one of the worms needs to be killed to end the fight entirely, so attacks should be focused on only one worm if possible. Phase 1 measures to avoid attacks still work in this phase, although dashing is notably riskier for avoiding rams from either worm.

In Expert Mode

Astrum Deus's segment count increases. When a worm reaches 50% HP in Phase 2, it begins replacing some of its regular lasers with blue-orange helical lasers, which are harder to dodge due to their higher speed and increased size. The mines will also slowly move towards the player when Astrum Deus is below 30% HP, making them even more dangerous. Sufficiently damaged segments will also begin firing independently from the laser barrages.

In Revengeance Mode

Segment count and movement speed are increased. Independently firing segments now fire faster. Players are inflicted by Extreme Gravity, which will make the fight harder by reducing players' flight times.

In Death Mode

Segment count, movement speed and rate of fire are increased. Astrum Deus can fly at any time in Phase 1 and will only leave mines while flying. The fight no longer ends when one of the worms dies. Instead, the other worm will enrage, will no longer use colors to show current behavior and will have access to all of its attacks. Because of that, it may be recommended to target both worms in Phase 2 instead of focusing on one.

General Tips

  • Disabling backgrounds can help players who have trouble focusing on all the different things that are going on during the fight.
  • In Revengeance mode and higher, using Adrenaline or Rage can remove a large chunk of Astrum Deus' health when it is low to swiftly end the fight.
  • Using the Overlay Minimap and changing its transparency with Page Up and Page Down keys can provide the player with icon of bosses that are too far to see without the Minimap, making it a useful tactic to aim at bosses.
  • Using the Rod of Discord can allow a quick escape, especially if you are walled by several mines.