Leviathan and Anahita

"...Two genetic misfits outcast from their homes..."

The Leviathan and Anahita are a duo of bosses that can be fought at any point in the game, but is intended to be fought during Hardmode. It is recommended that the player acquire post-Plantera equipment before engaging the bosses, as they are very challenging and require the management of two boss-tier enemies with several summons all at once.

Spawn
To begin the boss fight, the player has to kill the ??? in the Ocean. Doing this will spawn just Anahita at first, and The Leviathan herself will only spawn once Anahita reaches 40% health.

Behavior
This boss encounter is made up of two individual bosses: Anahita and The Leviathan. Both enemies must be defeated to count as a full kill and receive loot. Only Anahita is summoned at the start, but after she reaches 40% of her health, The Leviathan is summoned. She stops attacking the player and becomes invulnerable until The Leviathan reaches 40% health. They become invulnerable to damage if the player leaves the Ocean biome during the battle.

Anahita

 * She hovers above the player while periodically performing one of three attacks, all of them converging on the player's location.
 * Summons 8 water spears, which continue to travel after converging and inflict the Wet debuff for 4 seconds.
 * Summons 3 icicles, which home in on the player after converging.
 * Summons 6 treble clefs which move slower, linger for an extended period of time and inflict the Confused debuff for 2 seconds.
 * Below 70% health, she summons more projectiles during these attacks. This change is reverted while The Leviathan is alive and Anahita is above 20% health.
 * She additionally can summon Detonating Bubbles that inflict the Wet debuff for 7 seconds.
 * She generates an ice shield at 100%, 70%, and 40% health, rendering her invulnerable to damage until it's destroyed.
 * The ice shield blocks non-minion piercing projectiles.
 * When below 70% health, she will occasionally charge at the player 3 times.
 * She won't perform this attack if The Leviathan is alive and she is above 20% health.
 * She becomes enraged if The Leviathan is defeated first.

The Leviathan

 * She mainly stays on one side of the player while cycling through her attacks, switching sides if the player moves around her.
 * She fires meteors at the player, which inflict the Armor Crunch debuff.
 * She summons Aquatic Aberrations and Paraseas to attack the player.
 * When below 50% health, she pauses for a few moments before aligning with the player horizontally then charging at them.
 * She won't perform this attack while Anahita is alive and she is above 20% health.
 * She becomes enraged if Anahita is defeated first.

In Expert Mode

 * Anahita is much more aggressive and deals more damage.

In Revengeance Mode

 * The Leviathan shoots faster and can charge at the player below 70% health.

In Death Mode

 * Anahita has increased velocity and spends less time firing bubbles at the player.
 * After she charges, The Leviathan charges a second time.
 * Both bosses are always in their enraged state.

Aftermath

 * Once defeated, Giant Cursed Skulls will begin to drop Keelhaul.

Tips

 * Making 3-4 layers of platforms that are the whole length of the Ocean may make it easier to dodge their attacks.
 * Once the Leviathan has reached 50% of her health, care should be taken to be aware of where she is as she will start charging the player. Should she be on the left or right side of the player, it is important to dodge it either moving down or above where the Leviathan is going.
 * Using Water Candle, Chaos Candle, Battle, and Zerg buffs in combination will make ??? spawn over 5x more often, making the bosses much more readily available.
 * This will also increase the spawn rate of ocean enemies, so be cautious.

Trivia

 * Anahita's theme is Siren's War Cry, which was composed by the artist DM DOKURO.
 * Siren's War Cry is the only Calamity theme to not be featured in its own video, instead only appearing in an "Extended" version alongside the other themes for Leviathan and Anahita. This is due to the fact that Siren's War Cry was made sometime after the other two themes, in response to a rework to the fight which now included Anahita being fought on her own.
 * When The Leviathan appears, the theme changes to Forbidden Lullaby, which was also composed by DM DOKURO.
 * If the Calamity Music add-on mod is disabled, Boss 3 will play instead for Leviathan and Anahita.
 * The dual nature of the fight took inspiration from the Ornstein and Smough fight from Dark Souls.
 * In previous versions of the mod, Anahita had two color schemes with one randomly being chosen upon her spawning. Some of her features would be either greener or more blue. This was the reasoning for the Aquatic Heart having two variants based on color.
 * Originally, Anahita and Leviathan shared their lore entry.
 * Anahita was previously named The Siren. Prior to that, she was known as the Siren Lure.