The Celestials

The Celestials were a group of Hardmode bosses that could be fought after Plantera has been defeated. Defeating the Celestials would provide the player with 4 weapons, and after the Moon Lord has been defeated it will drop Lunar Fragments from the boss or treasure bag. They consisted of a group of bosses that would spawn on the progression of the fight, being Ember, Nova, Carina, Aquila, and Astra, from beginning to end.

Spawn
The Celestials were summoned with a at night time anywhere in the Surface.

Behavior
The Celestials had five phases, each with their own attacks and different speed. They progressed through these phases as they lose health.

The Celestials could spawn Celestial Watchers, which acted as their shield and primary attack, as they fired lasers throughout the fight. They were colored differently depending on what Celestial was being fought. Astra, however, summoned Astra's Gazers instead. The Celestial Watchers could be killed but respawned in the next phase.

Phase 1 - Ember

 * Ember occasionally charged at the player, with long gaps in-between charges.
 * Occasionally shooted clusters of meteors, similar to the ones fired by the Solar Pillar.
 * Passively rained meteors from the sky.

Phase 2 - Nova

 * Transitions at 75% health.
 * Nova frequently charged at the player.
 * Shooted a wave of stars.

Phase 3 - Aquila

 * Transitions at 50% health.
 * Aquila charged at the player frequently, but at a slightly slower rate than Nova.
 * Created portals that shooted lightning at the player, similar to the ones summoned by the Vortex Pillar.

Phase 4 - Carina

 * Transitions at 25% health.
 * Carina charged at the player at the same rate as Aquila.
 * Created portals that shooted beams left, right, up, and down.

Phase 5 - Astra

 * Astra spawned when The Celestials health dropped to 0.
 * Unlike other Celestials, she couldn't be damaged while Astra Gazers are alive.
 * Charged at the player.
 * Shooted a burst of 3 Astra Shots.

Quote

 * "You can't stop what's already been started." (upon death, appears 4 times in the chat)

Trivia

 * The Celestials were themed around the Lunar Events, and most of their attacks are based on existing attacks from those events.
 * Ember was themed around the Solar Pillar
 * Nova was themed around the Stardust Pillar
 * Aquilla was themed around the Vortex Pillar
 * Carina was based around the Nebula Pillar
 * Astra was a combination of all The Celestials
 * The Celestials' theme was called "The Cosmic Web" and was composed by Ranipla and GENIH WAT. The song is in four parts, each representing one celestial.
 * Astra's theme was called "Coherence Complex", which was also composed by Ranipla and GENIH WAT. This song combines leitmotifs of all four celestials.
 * An unused [[File:Celestial Moon.gif]] moon sprite for the Celestials exists within the mod's source files.
 * They were removed as ThatOneJuicyOrange, the mod's creator, found them gimmicky and boring. The Eldritch Keepsake was added to remember them.

Lore
Infusing all four lunar forces, Astra is but a singularity, Born within the everlasting circle of the moon, she is just a fraction of power that was once sealed. Guardian of the celestial forces and one of the Moon Lord's most trusted servants, she was.. Unbeknownst to most, she was born without a soul, or a mind, she only knew to serve and destroy.

Soon, four powerful warriors would rise and the celestial forces, which she guards, would break out and manifest into these warriors, and it would transform them into four towers of destruction. Astra, against her will would absorb all four powers, and she turned to consisting of four different shades, each of which would represent those very forces - Nova, Aquila, Ember and Carina.

Sent to earth by the command of the Moon Lord, they helped aiding the cult into capturing innocent creatures for their liking to sacrifice them to the moon god. Beneath that, they began searching a powerful being, may it be human or another sentient being, to drive out their own will, so that they could aid the god in conquering these lands.