Guide:Arena

An Arena is generally an area that the player builds where they can face a Boss or other significant challenge more easily. Each arena can be different for each boss, some consisting of a flat area or multiple layers of Platforms supported with Statues.

General Arenas

 * Location: An arena is better built away from Bases so NPCs won't get hurt or killed. It's better built near the ground, far from Space so there won't be any unwanted Wyvern spawns during a bigger fight.
 * Main Structure: Sometimes, the shape of the arena depends on the Boss or Event and how the player decides to fight it. A typical arena usually consists of multiple long rows of Platforms, supported with Campfires, Heart Lanterns, Honey placed in Bubbles and Heart Statues to increase Health regeneration. A Mage will also want to place Stars in a Bottle and Star Statues to regain Mana more easily.
 * Nurse Room: You can build a house for your Nurse NPC somewhere in or near your arena. The House must have a Bed, so in the middle of the battle you can use a Magic Mirror or Recall potion to visit the Nurse and get instant healing.
 * Teleporters: Once you have killed a Mechanical Boss and had the Steampunker move in, you can buy and use Teleporter to devastating effect. When wired to Pressure Plates placed above them, you can instantly transport across the arena, making a boss much easier to dodge.

Eye of Cthulhu


An arena for the Eye of Cthulhu should be large enough to dodge and maneuver around in. The recommended size is just about the width of the screen.

Several rows of wooden platforms can make dodging simpler. As the fight will be at night, add torches to help visibility.

Another arena is simply a flat surface, made out of either Platforms or Blocks. This allows you to dodge the Eye by running to the left or the right with Swiftness Potions or Hermes Boots.

Eater of Worlds


The player must be in The Corruption to summon the Eater of Worlds; moving too far away from the biome during the battle will cause it to flee.

The Eater of Worlds is a very large Worm enemy, so dodging it may prove to be difficult. Make the arena fairly tall, thin, and easily climbable with many Platforms. That way, not only you can see it coming, but this will force it to climb in a relatively straight line, leaving large portions of its body exposed, and vulnerable to piercing attacks.

The above setup assumes the Eater of Worlds is fought on the Surface. If you are breaking Shadow Orbs, hollowing out an entire arena every third orb or escaping to a surface arena may not be practical; you should still modify the terrain around you to have a clear path of escape from the chamber where the Orb is located and ideally, easy access to a cleared space with good horizontal clearance and any hazardous terrain smoothed out or boarded over.

Skeletron


The entrance area to most dungeons can often be modified into a more desirable arena if needed. Most important is that you have room to dodge the hands, as well as enough vertical space to avoid getting trapped when Skeletron's head begins to spin.

Take caution when modifying the structure of the dungeon. If the floor is modified too much, this may prevent future bosses (Lunatic Cultist) from spawning.

A simple, effective, and time-consuming approach is to build a Sky Bridge with Minecart Tracks. Then spawn Skeletron, hop in your minecart, and speed away. Skeletron will chase after you but will not catch you. Kill it with ranged attacks. If you run out of tracks before you kill it, die, and add more tracks before you spawn it again.

Invasions


Invasion events such as the Goblin Army, Pirate Invasion and Martian Madness can only be fought near the Spawn, or somewhere close to an NPC.

Before starting an event, make sure NPCs are protected, otherwise they will be attacked and possibly killed during the fight. Placing a block in front of a Door will prevent enemies from forcing them open and killing the NPCs.

If defended properly, the events can then be easily fought on a player's Base, using the Houses built as cover. Since most enemies from invasions lack the ability to attack through walls, they can be easily killed while standing above them in an enclosed room. However, make sure to have an exit ready for when the enemies that can attack through blocks spawn.

King Slime
This boss is relatively easy however, and you don't need an arena to defeat it. There is an easy way to defeat him quickly, pile up some rope maybe 20-30 blocks in the air and use ranged attacks from from above. He can jump, but he cannot teleport to you. Making the ropes higher than he can jump is essential to defeating this. Both he and all slimes he creates will be defeated by this easily.

It is no longer possible to exploit the King Slime's large size in versions, as he can now teleport to your location.

Wall of Flesh
The Wall of Flesh, more than probably any other boss, benefits from having an arena prepared before engaging. Even experienced players wishing for a quick fight should ensure that the path behind them is clear before summoning it.

The simplest arena is a long bridge of about 750 blocks with some space above it for the player to maneuver. Placing the player out of danger from falling into lava and ensuring that they can keep a steady pace of progression allows the fight to go quickly and smoothly. Players may also wish to place lights along the bridge.

Note that Underworld map generation tends to place Ruined Buildings towards the middle third of the map, leaving the eastern and western wings mostly clean.

The Wall of Flesh begins its attack from whichever side of the Underworld's map edge you're closest to. This allows you to control its direction of approach. Fight in the direction you're most comfortable with.

Killing the Wall of Flesh will generate a bricked-in treasure box above your bridge. The bricks can serve as kill-markers, but they may also interfere with jumping if your next fight runs close to that spot. The bricks can be mined to keep a clear Arena.

The Destroyer
Your Eater of Worlds arena should also serve as an arena for fighting The Destroyer as both bosses act in a similar way, however The Destroyer does not need Corruption present to be summoned.

Alternatively, you could start by building around 250 feet into the air. Create a rectangular box at the top. The rectangular box should be around 5 blocks high, and 20 blocks wide. If built tall enough, the box will make the Destroyer unable to reach the player while also protecting them from its lasers, leaving only the Probes as a threat.

The Twins
While the Twins can be defeated with just a regular arena, building a long skybridge is very effective against them due to their movement patterns; when running on a straight line it's hard to get hit by their charge attacks and Retinazer's lasers, leaving Spazmatism's Cursed Fireballs on its first phase as the only threat.

Plantera
Build a long hallway, preferably about six blocks high and 100-200 blocks wide, with teleporters at each end of the hallway. When you spawn Plantera, have it go through the hallway, and run to the edge of it to one of the teleporters. When Plantera charges after you teleport to the other end of the hallway and shoot down the hallway. Repeat this process until Plantera has been defeated.

Golem
The Golem can only be summoned in the Lihzahrd Altar room in the Jungle Temple. The Boss cannot go through blocks, so building small walls with blocks will greatly hinder its movement, making it much easier to kill. Additionally, the Lihzahrd Traps found in the Temple can be used to deal some extra damage to the boss.

Moon Events


The Pumpkin and Frost Moons are much easier to handle with the proper arena.

A flat surface about 168 blocks wide (See NPC spawning) will focus all spawns on the arena. Above it there should be a long platform of the same width, high above the ground in order to keep the enemies out of melee reach. Since the player will mostly focus on the Boss enemies on the later Waves, it's a very good idea to support the Arena with a Lava Pit and Traps to take out the weaker enemies more easily. As always, Campfires, Heart Lanterns, Honey and Heart Statues are good to place.

Spike Ball Traps and Super Dart Traps can potentially cover the entire arena, while Spear Traps and Flame Traps can be placed at the Lava Pits to make full use of their limited reach but high damage.

Moon Lord
The Moon Lord is the Final Boss in the game, and generally considered the most difficult.

The player will need a big arena, with ample room to dodge all of its attacks. A roof can be made with solid Blocks in order to prevent the Phantasmal Deathray from connecting, but this may hinder vertical mobility.

Alternatively, a long Skybridge made with Asphalt blocks or Minecart Tracks can also make it significantly easier to dodge by running in one direction. Teleporters should also be placed at the end of the bridge, in order to loop through it while running.

Dungeon Guardian
While it's not mandatory to defeat the Dungeon Guardian, some players choose to do so to obtain the Bone Key it drops.

The enemy can be easily defeated by outrunning it with Wings or flying Mounts, but building an Arena with automated Teleporters or Minecarts will make it significantly easier to kill. A Skybridge can also make the fight far simpler.

Ocean Enemies
Ocean enemies can be farmed by building a long bridge over the ocean. This is a good way to farm Pirate Maps, key molds, glowsticks, shark fins, black ink, and, of course, coins. Build two layers of platforms - The first layer should be 2 blocks under water, the second one on top of the water. In the 2nd layer, stand in a small pool of water so that all of the mobs swim up towards you. This will cause water mobs to jump out of the water onto the platform. The Spider Staff is good for automatically killing the mobs as they obediently stay out of the water and is very easy to obtain. Another way to kill them is by connecting one-second timers to Spear Traps or Spike Ball Traps from the Lihzarhd Temple.