Empress of Light

The Empress of Light is a Hardmode, post-Plantera boss fought in the Hallow. While she can be summoned as soon as Plantera is defeated, she is significantly more difficult than most Hardmode bosses and will typically require post-Golem gear. Fighting the Empress of Light is completely optional and is not required to progress.

Summoning
The Empress of Light can be summoned by killing a Prismatic Lacewing, which is a rare Critter that spawns in the surface Hallow during the night once Plantera has been defeated in the world. As it is a rare creature, it can be detected by the Lifeform Analyzer. The Prismatic Lacewing must be killed at night to summon the boss.

Like most critters, the Prismatic Lacewing can be caught with any bug net, which can then be released, and killed, by the player manually.

Behavior
If she is fought during the day, all of her attacks will deal massive amounts of damage (Like Skeletron, Skeletron Prime, and the Dungeon Guardian), effectively one-hit killing the player. She will always drop the Terraprisma if all damage dealt to her was during the day.

She will transition into her second phase once she is below half health. Her attacks will also occur with shortened intervals.

Attacks

 * Prismatic Bolts - An array of prismatic bolts are launched that will home in on the player. These projectiles are not very maneuverable and can be dodged by swerving downwards then upwards.
 * Dash Attack - The Empress of Light will spend one second charging before charging horizontally at the players direction.
 * Sun Dance - The Empress of Light will dash towards the vicinity of the player then emit light beams in all directions. Dodged by immediately moving away.
 * Everlasting Rainbow - 16 projectiles are emitted that will spiral out in a clockwise direction then spiral back in the same direction. The trails left by this attack linger for a few seconds and do damage.
 * Ethereal Lance - The Empress of Light will spawn many swords at various angles in quick succession with their paths indicated by straight lines. These swords will travel along their displayed path after a brief pause. **Note that the swords deal no damage when they are still stationary.

First Phase
Attacks are in this particular order.


 * 1) When spawned, the Empress of Light will hover for a few seconds before executing her prismatic bolts attack.
 * 2) Dash Attack
 * 3) Sun Dance
 * 4) Dash Attack
 * 5) Everlasting Rainbow
 * 6) Prismatic Bolts
 * 7) Dash Attack
 * 8) Ethereal Lance
 * 9) Repeat of steps 4 - 8.
 * 10) Repeat of steps 2 - 9.
 * 11) Steps 9 and 10 repeated indefinitely until second phase.

Second Phase
Attacks are in this particular order.


 * 1) She will disappear for a second then reappear above the next estimated location of the player.
 * 2) Ethereal Lance (The swords will be spawned in parallel to each other and will converge on the player.)
 * 3) Prismatic Bolts
 * 4) Dash Attack
 * 5) Ethereal Lance (The swords will be sequentially spawned in a rotating fashion), in conjunction with Everlasting Rainbow shortly thereafter.
 * 6) Prismatic Bolts in conjunction with Sun Dance shortly thereafter. **Very difficult to dodge.
 * 7) Ethereal Lance
 * 8) Dash Attack
 * 9) Prismatic Bolts (Spawned in a circle around the boss)
 * 10) Ethereal Lance (The swords will be sequentially spawned in a rotating fashion)
 * 11) Indefinite repeat of steps 2 - 9.

Tips

 * It would be wise to defeat Golem first, so the Cosmic Car Key will become available.
 * On Expert Mode and above, the Witch's Broom is a good substitution for Cosmic Car Key, which can be obtained during Pumpkin Moon.
 * For Master Mode, The Black Spot is another option for being available during Pirate Invasion.
 * Not only does the Empress have to be killed during the day to gain the Terraprisma, but all damage she receives must be during the day as well. Any attack from the Empress during the day will instantly kill the player as well as have a yellowish hue.
 * Consider using a Bug Net to capture any Prismatic Lacewings when you see them, rather than killing them immediately. This will allow you to easily fight the Empress at a time of your choosing once you are prepared. Note that if the Prismatic Lacewing is released outside of the Hallow, it will immediately disappear.
 * While they immediately disappear, it is still possible to kill the Prismatic Lacewing outside of the Hallow. This is done by having a weapon selected, placing the Lacewing from your inventory, then spamming left-click so that you immediately attack, killing it in time to spawn the boss.
 * It is helpful to obtain the Master Ninja Gear before fighting the Empress, as the dash ability, as well as the chance to completely dodge an attack, can be extremely useful during the fight, especially if the player wishes to fight her during the day. What's more, the accessory is obtainable as soon as Plantera is defeated.
 * Additionally, the Shadow Dodge buff from Hallowed Armor can also be helpful since it guarantees to dodge an attack every 30 seconds. Furthermore, Mechanical Bosses always drop Hallowed Bars when defeated.
 * Be careful using weaponry that deals splash damage or has a high area of effect, as killing the Prismatic Lacewing at day makes it so the Empress of Light will spawn as a much more powerful boss with one-shot-kill attacks dealing an average of 20,000 damage a hit.
 * In order to prevent accidentally summoning the boss, the Guide to Critter Companionship prevents the player from damaging critters, including the Prismatic Lacewing.
 * The Rod of Discord can prove extremely useful during the fight in order to dodge her strong attacks.
 * Since the Empress' attacks can instantly kill the player during the day, it can be used regardless of whether the player will take damage due to the Chaos State debuff or not.
 * Equipping an item that allows the player to dash can prove extremely helpful in dodging her attacks.

Trivia

 * This boss was described as "a beautiful bullet hell" by Cenx before 1.4 was released.
 * The Empress of Light is one of the two new bosses added in the 1.4.0.1 update, the other being Queen Slime.
 * She and Plantera have the only musical instrument drops of any boss, with The Axe and the Stellar Tune having the same drop chance as well.
 * The Empress of Light is one of 5 bosses with exclusive music, the others being Queen Slime, Plantera, Duke Fishron and Moon Lord.
 * The Empress of Light is one of the 3 out of the 10 hardmode bosses that are not necessary to beat the game.
 * The Empress of Light can be seen as the counterpart to Duke Fishron in many aspects. Both have noble titles, are generally meant to be fought after Golem and are summoned using a critter that can be obtained earlier in Hardmode.
 * The Empress' wings bear a striking resemblance to that of Cenx's Wings.
 * The color of her attacks will change from rainbow to yellow during the day, indicating that the attacks will do massive damage.