Events (some also known as invasions) are temporary occasions where varieties of special enemies spawn, most at elevated spawn rates, even near NPCs, and attack players. Some events can occur randomly during gameplay, while others can be triggered via certain summoning items or special circumstances. Events spawn their own unique enemies not seen during ordinary gameplay, which can, in turn, drop unique items that are only obtainable within the event. Some events also bring unique visuals and a unique atmosphere, such as an altered moon and noticeable shaders applied to the screen. Events also are accompanied by their own special music, adding on to their theme. Depending on the particular event, they may last until a certain time limit is reached, or until a certain number of enemies are defeated.
On the Desktop version, Console version, and Mobile version, a progress bar can be seen in the bottom right corner of the screen to indicate how far the player has gone into the event, and how far they are from completing it. It only appears during invasion-style events (Goblin Army, Old One's Army(Desktop, Console and Mobile versions), Frost Legion, Pirate Invasion, Pumpkin Moon, Frost Moon, and Martian Madness(Desktop, Console and Mobile versions)) and will not appear during events that are time-limited (Blood Moon, Rain, Slime Rain(Desktop, Console and Mobile versions), Sandstorm(Desktop, Console and Mobile versions), and Solar Eclipse).
Note that certain invasions (Goblin Army, Frost Legion, Pirate Invasion, and Martian Madness) have location requirements. The player must be no deeper than 67.5 tiles below the surface, and the player must be within 187.5 tiles horizontally of the location of the invasion. If the invasion has reached the center of the world, then the horizontal check can also be satisfied by the player being within 187.5 tiles horizontally of any town NPC, although at a reduced spawn rate. The town NPC's vertical position is not checked and so they can be housed far above or below the arena.
There are (Desktop, Console and Mobile versions)19 / (Old-gen console and 3DS versions)8 different events and invasions.
- Occurs the night after a boss or invasion has been defeated, or randomly at night after the Moon Lord has been defeated.
The Lantern Night is an event that occurs in celebration of the player's victory over a boss or invasion. The Party Girl will sell the Release Lantern and the player will have a flat +0.3 increase to their Luck stat.
During such a night many lanterns can be seen rising up into the sky in the background.
- Occurs randomly.
Rain affects all surface biomes for its duration. Each Rain event lasts for 24 in-game hours (24 real-world minutes), spanning both day and night portions. When a player is in a Snow biome during Rain, it appears as a Blizzard, causing snowfall volume to increase. Rain also increases cloud cover.
Other effects include the following:
- Occurs randomly while Wind speeds are above 30 mph.
A Sandstorm is an event specific to the Desert, they will not occur anywhere else. A Sandstorm occurs in all Deserts at the same time. While this event is active, the Mighty Wind debuff will be continuously inflicted upon the player.
During a Sandstorm, many particles of sand can be seen flying across the screen, the color of these particles will depend on whether the Desert is regular, Corrupt, Crimson, or Hallow. Vision is also limited.
- Occurs randomly.
- Occurs randomly.
A Thunderstorm is a rare weather event where both the Rain and Windy Day events combine. During a Thunderstorm, lightning will occasionally flash on the screen and the lighting will dim even further than the Rain. The wind also blows much more ferociously than normal. All effects from the Rain event also occur during a Thunderstorm.
- Occurs randomly at night.
Blood Moons are signaled by the status message "The Blood Moon is rising...". All the water in the world, even underground, will turn blood-red for the duration of the event, including rain and the moon itself. (Desktop, Console and Mobile versions) A red filter will be applied to the screen when the player is on the surface layer. The ability to speed up time by sleeping in a bed is also disabled.
The event will significantly boost spawn rates in surface biomes, as well as spawn new and dangerous enemies, while also changing their behavior and spawning conditions.
(Desktop, Console and Mobile versions) Fishing Power is increased by 1.1 times. However, fishing could also bring about unique enemies.
The Goblin Army is an event where unique Goblin enemies spawn. When a Goblin Army is approaching, one of the two following status messages will appear: "A goblin army is approaching from the west!" / "A goblin army is approaching from the east!"
During the event, five ((Desktop, Console and Mobile versions) six during Hardmode) different types of goblins will spawn:
Although they do not appear in the Goblin Army, Goblin Scouts can be found rarely on the outer thirds of the map. They drop Tattered Cloth which is used to craft the Goblin Battle Standard, the summoning item for this event.
Slime Rain is an event where different variations of slimes constantly fall from the sky until the day or night is over. If the player kills 150 slimes before the event ends naturally, King Slime will spawn. If King Slime was defeated previously, then only 75 slimes need to be killed before he spawns.
Many types of slimes spawn, including:
After King Slime is defeated, the event will immediately terminate.
The Old One's Army is a unique Dungeon Defenders 2 crossover event that can be initiated after rescuing the Tavernkeep, who can be found on any layer after defeating the Eater of Worlds/Brain of Cthulhu. The objective is to protect the Eternia Crystal from waves of enemies which appear from Mysterious Portals, seeking to destroy it. If the Crystal is destroyed by enemies, the event terminates. If it is kept safe until all waves are cleared, the event is won.
Both the Crystal and its Stand are purchased from the Tavernkeep NPC for coins. Players are inflicted with the Creative Shock debuff for the duration of the event, which prevents the removal or placement of blocks during the entire event within a certain range.
Each wave becomes progressively more difficult and features larger varieties of enemies. Additionally, the entire event is expanded in difficulty depending on player progression. If triggered before any Mechanical Bosses have been defeated, the event consists of 5 waves. If triggered after at least one Mechanical Boss is defeated, the event consists of 7 waves. Once Golem has been defeated, the event becomes even more difficult with the boss Betsy spawning in the final wave. Betsy will only spawn once during each invasion, and defeating it will complete the event. The event also contains 2 mini-bosses, the Ogre and the Dark Mage.
The following enemies are exclusive to the event:
- Initiated when around 100 torches accumulate in close proximity anywhere below the Surface layer.
The Torch God is a mini-event that happens when 100 torches accumulate in close proximity underground. The placed torches begin launching small fireballs at the player, extinguishing themselves in the process. The fireballs deal 40 / 80 / 120 damage, and they travel in straight lines through blocks. They can also spawn from torches located off-screen.
When all torches are extinguished, the event ends. After a brief period, the torches reignite, and if 100 or more torches have been activated, the Torch God's Favor will appear in the player's inventory. The player can not challenge the event again once the player has a Torch God's Favor either in their inventory or consumed, and must create another character to do so. A player that has not consumed a Torch God's Favor can continuously challenge and complete the event and obtain more Torch God's Favors, as long as they do not have one in their inventory.
- Summoned with a Snow Globe.
The Frost Legion is an event that functions similarly to the Goblin Army, but it requires an item to start the event, which is only attainable in Hardmode. During Christmas, enemies will drop presents. If the world is in Hardmode, these presents have a 1/13 (7.69%) chance of containing a Snow Globe, which is used to spawn the Frost Legion.
During the event, three different types of unique snowmen will spawn:
All of the snowmen drop Snow Blocks, technically granting the player a way to obtain infinite amounts of Snow.
The Solar Eclipse is a Hardmode event where the sun will rise, obscured by the moon, dramatically reducing natural light to a level darker than nighttime. Normal biome enemy spawns are replaced with special enemies that can spawn near NPCs, much more frequently and in greater numbers than usual. On the Desktop version, Console version, and Mobile version, it can be skipped using an Enchanted Sundial.
During the event, the following enemies will spawn:
After all three mechanical bosses have been defeated:
- Reaper((Desktop, Console and Mobile versions))
After Plantera has been defeated:
- Butcher(Desktop, Console and Mobile versions)
- Nailhead(Desktop, Console and Mobile versions)
- Deadly Sphere(Desktop, Console and Mobile versions)
- Psycho(Desktop, Console and Mobile versions)
- Dr. Man Fly(Desktop, Console and Mobile versions)
- Mothron(Desktop, Console and Mobile versions)
- Baby Mothron(Desktop, Console and Mobile versions)
A Solar Eclipse is always terminated upon dusk.
The Pirate Invasion is an event that is very similar to the Goblin Army. It can spawn randomly, or be summoned by the use of a Pirate Map, which can be obtained from killing any enemy in the Ocean biome during Hardmode.
During the event, (Desktop, Console and Mobile versions)7 / (Old-gen console and 3DS versions)6 different pirate themed enemies will spawn:
The event is completed after a certain number of pirates have been defeated. Afterward, the Pirate NPC will move in.
- Summoned at night with a Pumpkin Moon Medallion.
The Pumpkin Moon is a Halloween-themed event that, unlike most other events, takes place in distinct waves. There are 15 waves in total, which grow harder as the night wears on, culminating in the "Final Wave", which lasts for the remainder of the night. The Pumpkin Moon can be skipped using an Enchanted Sundial(Desktop, Console and Mobile versions).
The Pumpkin Moon has seven unique enemies, in increasing order of difficulty:
- Summoned at night with a Naughty Present.
The Frost Moon is a Christmas-themed event, using the same wave system as the Pumpkin Moon. The Frost Moon also has an additional five "bonus waves" after the "Final Wave", increasing the wave maximum to 20. Enemies have similar behavior to Pumpkin Moon counterparts, but are tougher, making this event the hardest on the Old-gen console version and Nintendo version. The Frost Moon can be skipped using an Enchanted Sundial(Desktop, Console and Mobile versions).
The Frost Moon has 11 unique enemies:
Although there are no rewards for surviving the event, besides an Achievement, the enemies can drop unique items.
- Initiated by letting a Martian Probe escape from view after detecting a player.
The Martian Madness event is a post-Golem event with an alien invasion theme. It is unique from the others in that in order to start it, it is required to encounter a Martian Probe randomly in the outer parts of the surface and space levels of the world and move into its light. Once the probe detects the player, it needs to leave the screen without being destroyed.
When triggered UFOs start flying in the background.
The Martian Madness event features 11 unique enemies:
The event is completed after a certain number of Martians have been defeated.
- Initiated after defeating the Lunatic Cultist.
The Lunar Events is a unique type of event that spawns four different pillars, the Celestial Pillars, spread evenly across the world. While in the proximity of a pillar, respectively-themed enemies spawn. There are four different pillars: the Solar Pillar, the Vortex Pillar, the Nebula Pillar, and the Stardust Pillar. Initially, all pillars are surrounded by a protective barrier. In order to damage and eventually defeat a pillar, a certain number of enemies related to said pillar needs to be defeated.
There are numerous unique enemies in this event:
After defeating all four pillars, the Moon Lord will spawn. The event is completed once the Moon Lord is defeated or the player dies during the battle.
- On the Nintendo version, the music for invasions is played throughout the entire world, regardless of if there's any enemies, until it is cleared.
- Desktop 1.3.2: Party event added.
- Desktop 220.127.116.11: Martian Madness, Slime Rain, and Lunar Events added. Invasion Events now have a progress bar, showing how far along the player is towards completion. Event enemies now run away when the event is over.
- Desktop 1.2.4: Fixed bug where spawn rates would increase underground when a moon event is happening. Invasion summon items will no longer be consumed if no invasion would happen using it.
- Desktop 1.2.3: Invasions can now spawn enemies anywhere near friendly NPC instead of just the middle of the world.
- Desktop 1.2: Solar Eclipse, Rain, and Pirate Invasion events added.
- Desktop 1.1.1: Frost Legion event added.
- Desktop-Release: Introduced Goblin Army and Blood Moon.
- Switch 1.0.711.6: Introduced Goblin Army, Blood Moon, Frost Legion, Solar Eclipse, Rain, Pirate Invasion, Martian Madness, Slime Rain, and Lunar Events.
- Console-Release: Introduced Goblin Army, Blood Moon, and Frost Legion.
- Mobile 18.104.22.168: Introduced Slime Rain, Martian Madness, and Lunar Events.
- Mobile-Release: Introduced Goblin Army, Blood Moon, and Frost Legion.
- 3DS 1.03: Frost Moon Added.
- 3DS-Release: Introduced Goblin Army, Blood Moon, Frost Legion, Solar Eclipse, Rain, Pirate Invasion, and Pumpkin Moon.