Terraria Mods Wiki
Eridanus, Champion of Cosmos
AI TypeEridanus AI
Damage150 / 300 / 450
Max Life500,000 / 1,000,000 / 1,500,000
10% (damage reduction)
KB Resist100%
Immune toChilledOn Fire!SuffocationLovestruckConfusedFargo's Mod/LethargicFargo's Mod/Clipped WingsFargo's Mod/Time FrozenFargo's Mod/Lightning Rod
Map Icon Eridanus (Fargo's Mod).png
Map Icon

"The stars are aligning..."

Eridanus, Champion of Cosmos is a post-Moon Lord boss. It is the strongest Champion, and also the only one to be considered a boss.


Eridanus does not spawn on its own and must be summoned by the player by using the Sigil of Champions while in Space. When summoned, a brief animation will play where a large turquoise vortex forms above the player, from which Eridanus emerges.


Eridanus’ attacks are all based on the Force of Cosmos’s enchantments, with a few attacks being based on the Moon Lord as well as the moon in general.

Expert Mode[]

Increased stats and gains access to several deathray attacks in Phase 2.

Eternity Mode[]

Eridanus now enters phase 2 at 80% health, and its second phase attacks are vastly improved. In addition, it gains a new 3rd phase at 20% health.

First phase[]

Eridanus follows a set pattern, repeating after completing the final attack. It will glow in the color of the respective attack whenever using them.

  • Eridanus forms a ring of solar fireballs around itself, then charges towards the player 3 times from either the left upper side or the right upper side. At the end of the third charge, the ring launches its fireballs outwards, each of which gain homing properties after flying for some time.
  • Eridanus creates a vortex at the player’s current location, which forms the second after to attract the player towards it. While this happens, it rapidly shoots 3-way lightning bolts that rotate clockwise. Eridanus will actively avoid the player during this phase to minimize contact damage.
  • Eridanus stands a certain distance next to the player, then starts shooting 2 arcs of nebula projectiles around the player. A reticle then appears, which predicts the player’s movement for 2 seconds before bombarding meteors at the reticle's position (telegraphed by a purple flash right before a bombardment). A new reticle will appear 3 more times.
  • Eridanus stops time in a burst of inverted colors, then spawns multiple rings of flow invader projectiles around the player (with all the projectiles being an equal distance from one another), that slowly converge after time resumes.

Eridanus goes into phase 2 after reaching 50% health (80% health in Eternity Mode). During the phase transition, Eridanus clears all projectiles and temporarily goes invulnerable/passive before releasing a pale afterimage to signify the transition.

Second phase[]

As with the first phase, Eridanus follows a set pattern that repeats after the final attack. In Expert Mode, additional attacks are inserted between its pillar-themed attacks; in Eternity Mode, many of these attacks are amplified.

  • Eridanus’ solar attack is improved, making the charges faster and used in quicker succession.
    • Eternity: Each solar dash terminates in a six-way burst of solar chain explosions that slowly radiates outwards; one of these chains will always be aimed at the player's current position.
  • Expert: Eridanus moves above the player before charging downwards to create a big deathray, which then spawns more deathrays along itself that shoot out horizontally. Each deathray is telegraphed by a smaller projectile.
    • Eternity: The horizontal deathrays slightly home onto the player's position.
  • Eridanus’ vortex attack is improved, spawning faster, and the 3 lightning bolts rotate even faster anti-clockwise.
    • Eternity: The 3 lightning bolts are even faster/thicker, and the vortex now frequently fires rings of electric spheres.
  • Expert: Eridanus visually charges up and summons V-shaped rows of cosmic spheres above and below the player, which converge while leaving gaps to dodge through. After summoning three pairs and completing his charging animation, Eridanus then dashes at the player in an horizontal manner, forming a huge deathray in its wake.
  • Eridanus’ nebula attack is improved, with the nebula arc being tighter, and the reticle meteor bombardments happening faster.
    • Eternity: Eridanus gradually rotates around the player while firing, ending the phase directly above them.
  • Expert: Eridanus shoots five rapid deathrays at the player, before ducking under the player and charging upwards, creating a bigger one that spawns even more deathrays in a messy spiral aimed roughly at the nearest player.
  • Eridanus’ stardust attack is improved, spawning even more flow invaders, which move faster.
    • Eternity: Now triggers much faster after his previous attack. The converging rings now alternate between evenly spaced rings, and solid rings with one gap to duck through.
  • Expert: Eridanus shoots fifteen deathrays at the player in rapid succession.

In Eternity Mode, Eridanus goes into its third phase after reaching 20% health.

Third Phase[]

All projectiles are cleared as Eridanus becomes engulfed in explosions and temporarily goes invulnerable. He then stops moving, traps the player in an arena of Phantasmal Spheres, and spawns 2 huge moons which circle around him clockwise, periodically crashing into each other. Every time the moons collide, he will launch one of 4 attacks in another set pattern:

  • Eridanus spawns a large ring of solar fireballs, which stop a short distance from itself before propelling themselves towards the player with slight homing.
  • Eridanus fires a dense ring of lightning bolts.
  • Eridanus launches a dense spread of nebula projectiles, which strongly home onto the player for 1 second before losing most of their homing power. The ring is extremely fast but has a blind spot directly in front of Eridanus.
  • Eridanus propels 2 rings of flow invaders, the first going much faster than the second.

As Eridanus nears death, the arena will gradually shrink, lowering the amount of space the player has to dodge attacks. However, Eridanus' attacks will also adjust themselves to compensate for the reduced room.


Source Debuffs
Eridanus, Champion of Cosmos (Fargo's Mod).png Contact
Phantasmal Sphere.gif Arena Border
Fargo's Mod/BerserkedBerserked
Fireball.gif Solar Fireball
Betsy's Breath.gif Solar Chain Explosion
On Fire!On Fire!
Lunar Portal.png Vortex
Lightning Orb.gif Lightning Orb
Nebula Blaze (projectile).gif Nebula Blaze Fargo's Mod/BerserkedBerserked
Fargo's Mod/LethargicLethargic
Meteor (1) (projectile).png Meteor On Fire!On Fire!
Broken ArmorBroken Armor
Stardust Enchantment (Fargo's Mod).png Time Freeze Fargo's Mod/Time FrozenTime Frozen
Flow Invader Minion.gif Stardust Flow Invader ObstructedObstructed
Phantasmal Deathray.png Cosmic Deathray
Phantasmal Sphere.gif Cosmic Sphere
Fargo's Mod/Curse of the MoonCurse of the Moon
Cosmic Moon (Fargo's Mod).png Cosmic Moon Fargo's Mod/Curse of the MoonCurse of the Moon
Broken ArmorBroken Armor


  • The music that plays during Eridanus' boss battle is Ordeal by Sakuzyo.
  • Eridanus is the name of a Supervoid, a vast starless area in space.
    • This name is also shared with a constellation often depicted as a river.
  • In-game, the white structures on Eridanus' shoulders and his hands will cycle through yellow/green/blue/purple glows, representing the four Celestial Pillars.
  • When Eridanus is defeated, he will uniquely explode into a rising pillar of teal explosions; in Eternity Mode, the moons from his final phase will also fall to the ground and explode into similar pillars on impact. All of these effects are purely cosmetic and deal no damage.
  • All of Eridanus' large deathray attacks inflict significant knockback even if the player has some form of knockback immunity.
  • If Deviantt is nearby during the fight, Eridanus will temporarily ignore the player to violently attack her with a nonstop barrage of deathrays; Eridanus' deathray attacks are coded to specifically deal increased damage to her. If killed that way, she drops Walking Rick.
    • Eridanus will also attack the boss version of the Deviantt in this way.
  • Eridanus' time freeze does not only affect the player, freezing all non-immune enemies (including bosses) and projectiles as well.
  • Eridanus' time-stopping attack is reminiscent of various attacks used by Sakuya Izayoi from the Touhou Project, where she freezes time and surrounds the player character with knives in the frozen time, which then converge on them when time resumes. A similar attack is also used by DIO in JoJo's Bizarre Adventure: Stardust Crusaders, with many aspects of the aforementioned character and the Stardust Enchantment Eridanus represents both being references to the show.
    • In addition, the sound effect when Eridanus uses the time freeze is the same sound effect used by DIO's stand The World in the 2014 anime adaptation (which is also used for the Stardust Enchantment). As of version 1.3.96, it has a similar visual effect as the one used by The World.
  • Before 1.3.96, Eridanus' phantasmal eye attack in his second phase was almost identical to the opening attack used by the boss Shen Doragon Awakened from the Ancients Awakened mod, who was programmed by the same developer.
  • Eridanus is the only Champion to have a proper name rather than only being referred to by their title. It is also the only one that drops items besides the two random Enchantments for their respective Force, that being Lunar Crystals.
  • If the player has the Yet Another Boss Health Bar Mod installed, Eridanus' health bar will be colored grey.
  • If the Boss Checklist Mod is installed, Eridanus' unique despawn message will be "Eridanus, Champion of Cosmos returns to the stars..."
  • The BestiaryBestiary entry for Eridanus, Champion of Cosmos: "This noble warrior once travelled the stars in search of worthy opponents. It settled nearby after encountering a certain mutated trio"


  • 1.3.96: Several attack reworks and visual updates.
  • 1.3.92: Now drops Lunar Crystals instead of the Eridanus Armor.
  • 1.3.9: Introduced.
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