Guide:Arena

Arenas are generally large boxed-in areas where the player can face a challenge in an environment they can control. They are generally designed to keep most enemies out while focusing on a Boss or other significant challenge. Construct arenas near a demon altar and providing easy access to it if it is possible.

Eye of Cthulhu
A highly recommended project for players who are about to summon their first boss. An arena for the Eye of Cthulhu should be large enough to dodge and maneuver around in, but small enough to seal off any enemies from wandering in and making the fight more difficult. A recommended size is just about the width of the screen.

Adding in a roof is also recommended to protect from airborne enemies and to keep retrievable ammunition from flying too far away. Making several large wooden platforms can make dodging simpler. As the fight will be at night, add torches to help visibility, including several in the ground underneath the arena.

Eater of Worlds
Location is important for an arena of this sort. Specifically, the Eater of Worlds can only be summoned in Corruption, and as of update 1.0.5, can only be FOUGHT in the corruption. If there is corruption close to your base, then using it is recommended. Otherwise, artificial corruption using Corrupt Seeds and/or Ebonstone is necessary. An area of just corrupted dirt will work sufficiently to summon the Eater of Worlds. Large chunks of Ebonstone (generally 300+) will also work.

The Eater of Worlds is, of course, a burrower, and will usually be offscreen and underground for much of the fight. A properly constructed arena can remove much of that advantage. Make the arena fairly tall and easily climbable with many wooden platforms. That way, you can not only see it coming, but have access to attacking its exposed body on every pass as well.



Goblin Army
Location is important for this arena as well. The goblins will naturally target your initial spawn, that is, the center surface of the map. So no matter what you actually have there, that's the general area where you will encounter goblins when they arrive. You may as well prepare a proper greeting for them.

Make sure there are no NPCs in this area, as they will be attacked and possibly killed during the fight. Goblin Sorcerers' attacks go through walls and they can teleport indiscriminately, so the only defense is to make sure that your NPCs are not nearby.

Flatten out an area and make sure that there are no pits or jumps. Walls are not necessary, as during an invasion the newly spawned monsters are the target rather than a distraction. Make certain that any platforms or areas can be easily and quickly reached from anywhere else on the screen, since most players will be looking to quickly close in on casters with their melee weapons.

King Slime
The King Slime only spawns some distance away from the center of the map. As most bases are started near the original center spawn, a secondary outpost is necessary to farm this creature. Additionally, to facilitate spawning, a large flat area covered in grass reduces wait times.

Though this boss is particularly easy, and an arena probably isn't necessary, it's possible to exploit this creature's unwieldy size and movement pattern to create an area where it is impossible for the player to take damage during the fight. Create several "foxholes" poking up to the surface, large enough for the player to jump (and shoot) through but too small for the boss to travel in. Then connect them all with a tunnel.

Demon Arena
Demons can be farmed in a similar way to Fire Imps, though it is important to remember that the Demon's projectiles can damage the player through one-block-thick walls, if you're in contact with that wall. In case Demons spawn below the platform you're standing on, you'll want to make that platform 2 tiles thick. Also, if Demons spawn below your tunnel, you will want to have solid ground or another platform built far below your tunnel to catch dropped loot (anything but lava). Demons will always fly as close to you as they can, putting them well within range of the Vilethorn, which will dispense with them rather quickly.

Bone Serpent Arena
Bone Serpents die if any one segment of their body, including head or tail, is reduced to zero health. The segment that dies is the only one that drops loot. If multiple segments die simultaneously, each drops loot, creating a much larger money output. This can be accomplished through creative use of Dynamite.

The first step of a bone serpent altar is to make a platform out of a dynamite-proof material such as Hellstone. Add a small lip to either side to prevent the dynamite from rolling off. Then, add a wooden platform up above the first platform.

To farm bone serpents, throw dynamite onto the first platform timed such that most of the serpent will be caught in the explosion. Then, jump up to the wooden platform straight above the dynamite (but out of range of the explosion) to lure the serpent right into your trap. This takes practice. If a bone serpent is caught just right, upwards of ten to twelve times the normal amount of loot is dropped. This more than covers the cost of the dynamite and actually turns a tidy profit.