Void Leviathan

The Void Leviathan is a post-Moon Lord boss that can be fought after Volcanox has been defeated and can be fought anywhere at night. He is one of the six elemental bosses. Defeating Void Leviathan will remove the Psychosis effect from the player.

Spawn
The Void Leviathan can be summoned with the Embryo of Existence anywhere at night.

Behaviour

 * During all phases:
 * The player will be inflicted with the Behemoth's Gaze debuff, which will damage them over time the further they stray away from the Leviathan, also decreasing defence and damage, but increased movement speed.
 * Rings of projectiles will be created around the player, which travel to the centre before disappearing.
 * In Awakened Mode, when it turns daytime, the boss will get an immense boost in speed and damage.
 * The tail takes 3x bonus damage, but if the player gets too close, it will shoot rings of high damaging void spines.


 * Phase 1
 * He spawns with a ring of barren souls around his head, which will increase in number depending on difficulty.
 * He will charge towards the player for ten seconds.
 * He occasionally wanders around the player and summons void runes, which explode into void flares.
 * Occasionally, he will stop for a few seconds and will shoot a barrage of void bolts from his body, repeating the process either two, three or four times depending on difficulty.


 * Phase 2
 * His shell falls off, revealing a phantom beneath, unable to damage the player via contact.
 * He will again wander around the player slowly.
 * Void's Orbs will spawn around 90 blocks away from the player, which will be shown on the map. Destroying these will make the Void Leviathan vulnerable for 15 seconds. In that period of time, he will charge insanely fast at the player.
 * An Elder Shade Wyrm will spawn when he reaches 30%, and  health.

Aftermath

 * Voidite Ore now generates in caverns.
 * Chaos Wraiths and Chaos Knights start spawning in.
 * After defeating the Void Leviathan, the screen will then shake and purple mist will appear. The following messages will then appear in order:
 * "You seek power..."
 * "But you haven't asked why."
 * "Does it matter?"
 * "You are almost there."
 * A few seconds after the last one, the purple mist will disappear, and the screen stops shaking.

Trivia

 * The theme of the Void Leviathan is called VOID and was composed by Universe.
 * Its old theme, "Eternal Dusk" was composed by Ranipla.

Lore
No breath of life is aware of the true intention of this creature. It is a monstrous giant serpent which originated from the depths of the void, with a name feared across all of Terraria, with some acknowledging it's unnatural and dangerous might. At the very best, the only force capable of opposing the leviathan was the creature of chaos, known for some as Azana. After a seemingly infinite battle, the serpent retreated back into the void, to hibernate and gather power. As the elements began to fall, it had absorbed the remaining everlasting essences and broke through the void, charging at the chaos being once again and yet was once again overwhelmed, but instead of ending the serpent, it had spared it's kind and helped to open the rift into the void, allowing its spirits and inhabitants to roam the world, empowering unknown places and tainting the night to be when the void would most shine. In return, the serpent gathered immense strength through an ancient moon god, capable of imprisoning the god of the underworld, Volcanox into damnation. But it had acknowledged that to assume the void's control, it would have to slay more than that. It had longed for one last thing to perfect its power - the soul of a powerful, even divine warrior. Causing an endless psychosis over the land, it eventually came to know that an embryo of his origin had been taken into this dimension, gathered by a warrior whose soul might be powerful enough to strengthen the serpent. Now it just lied in wait, for the warrior to make the first step...