Signus, Envoy of the Devourer

Signus, Envoy of the Devourer is a post-Moon Lord boss and is one of the Sentinels of the Devourer. It drops Twisting Nether which is a crafting material required to craft the Cosmic Worm.

Spawn
Signus is summoned by using the Rune of Kos in The Underworld at any time.

Behavior
Signus has 3 phases, each with their own unique behavior, appearance, and methods of attack. Signus cycles through these phases randomly; the same phase never appears twice in a row. Signus will always start the fight in Phase 1. Signus will do attack/s per phase before cycling to the next.

Throughout the fight, it summons Cosmic Lantern enemies that chase the player at high speeds in an attempt to deal contact damage. A maximum of 10 Lanterns can be summoned at a time.

Phase 1

 * Signus flies towards the player and teleports, each to random nearby locations. During this phase, Signus will take knockback, which can slow its advance. Below 50% HP, however, Signus will become completely immune to knockback.
 * As its health gets lower, it teleports more quickly and moves toward the player more quickly.
 * Below 30% health, Signus will not enter this phase.

Phase 2

 * Signus flies very quickly back and forth above the player and launches 3 bursts of 3 scythes that inflict Whispering Death.
 * The lower Signus' health, the faster it shoots these bursts.
 * Scythes eventually turn around in an attempt to hit the player again.

Phase 3

 * Signus flies above the player and lunges down at them extremely quickly.
 * As Signus' health gets lower, its lunges become even faster.
 * Signus occasionally spawns a wall of five Cosmic Lanterns in front of the player to block them.
 * Below 75% health, it summons trails of essence dust behind it while lunging. The essence dust explodes after a short delay.

In Revengeance Mode

 * After it teleports, Signus summons two pink Cosmic Mines, which chase the player and explode if in close proximity to them or after a short time.
 * The Cosmic Mine grows up to three times of its size before exploding.

In Death Mode

 * Signus is generally more aggressive and cycles through phases faster as its health decreases.

Tips

 * Building a large arena to dodge Signus' attacks is a good idea in order to give more room to move around.
 * Avoid traveling in a straight horizontal line while fighting Signus to avoid Cosmic Lanterns that spawn on each side of the player.
 * The Lacerator is great for destroying Cosmic Lanterns and for doing large amounts of damage to Signus while staying at a good distance.
 * Using the Seadragon along with Holy Fire Bullets can decimate Signus.
 * The Nuclear Fury is a great weapon for the Cosmic Lanterns as its area of effect can easily keep them at bay.
 * However, options such as Mistlestorm and Sanguine Flare will have much higher direct damage.
 * Elemental Axes paired with the Golden Gun and minion slot boosting accessories can be a deadly combination for defeating Signus.
 * Additionally, the life aura from summoner Tarragon armor instantly kills Cosmic Lanterns as they draw near.
 * The Molten Amputator is an excellent rogue option that deals great damage when the boomerangs stack on top of one another.
 * Signus' Cosmic Fireballs can be difficult to evade, thus using the Normality Relocator or a Rod of Discord is highly recommended.
 * The Ark of the Elements is still a decent option for Melee users.
 * Accessories such as the Flesh Totem and Elysian Aegis are extremely useful for dealing with Signus' massive contact damage.
 * If not already equipped, the Seraph Tracers are very useful for keeping up with Signus' speed.
 * Signus' AI is very similar to Brimstone Elemental's AI. Practicing her before fighting Signus may result in an easier fight.
 * It is possible to lure Signus out of The Underworld and on to the Surface. This can give the player much more vertical space to fight in, and will not change its behavior.

Trivia

 * Signus' theme is a segment from Servants of the Scourge, which was composed by the artist DM DOKURO.
 * This theme contains a motif from The Devourer of Gods' theme.
 * If the Calamity Music add-on mod is disabled, Boss 4 will play instead.
 * Despite being a boss, Signus will not drop a Treasure Bag in Expert Mode.
 * Signus was formerly referred to as 'CosmicWraith' in the mod's source files.
 * This was due to Cosmic Wraith being the working name for Signus during development.