Guide:Eater of Worlds strategies

The Eater of Worlds (or EoW) is arguably the most difficult boss a player will encounter. Preparation is almost vital, especially for the newer player. The following are some hints, tips, and strategies to help you defeat it.

Terrain preparation
Like all Bosses preparing for the fight is probably the biggest factor in your success.

Standing on a wide, elevated platform (with either glass or sky below it) helps tremendously, as you can see him approaching from below. The Platform can be further upgraded with several levels of Wood Platforms, to further increase the player's mobility.

Since Worms cannot navigate in the air, this setup will drastically reduce the Eater of Worlds' maneuverability. In such a scenario, the Eater of Worlds can almost always be evaded; getting hit is often a result of the player's own risk-taking to deal extra damage. Currently, the Eater of Worlds can only be spawned and fought in the corruption. As such, it would be best to create an artificial corruption area to fight in. Alternatively, you can find naturally occuring Corruption and create a "stadium" there. However, if you plan to create a floating stadium, you may have to hollow out a large section of the Corruption to do it, as going to far above the Corruption will be considered exiting it, causing the Eater of Worlds to despawn.

Armor and Accessories
Gold Armor is recommended but not necessarily needed, as it is not very hard to dodge the Eater of Worlds' attacks. Rocket Boots are recommended as they can help dodging.

Weapons
Because of its large size and multiple body parts, weapons that can deal damage to multiple sections should be used.

The Vilethorn and Vile Powder will not deal damage as quickly as other methods, but will have a balanced damage distribution throughout the entire body. Vile Powder has the advantage of being easy to find and free, while the Vilethorn is obtained from Shadow Orbs in the Corruption. Furthermore, these are very safe weapons to use against the worm: they can be placed before dodging the Eater of Worlds and running away, still damaging it. It is recommended to have 30 to 150 Vile Powder for this strategy, depending on how quickly you make the switch to higher damage weapons to finish off the Eater of Worlds.

Guns can be very effective at killing worms, particularly if Meteor Shot is used to pierce multiple segments. The Space Gun acts similarly, able to hit two segments in one shot. Bows don't have as fast a rate of fire, but by farming Devourers for their teeth and upgrading to Unholy Arrows, the piercing effect makes them a great choice. The Demon Bow is relatively easy to get by this point and will work well.

Non-explosive consumables, such as Shuriken and Throwing Knives, can be effective since their piercing attack will hit multiple segments while allowing the player to keep a safe distance. Spiky Balls are especially useful, as they can be thrown down where the Eater of Worlds is likely to surface, in the same manner as Vile Powder.

Flails can damage multiple segments and tend to damage the Eater of Worlds faster, but will also deal more focused damage, splitting the Eater of Worlds more often. They are excellent for killing smaller worms though.

Large swords like the Phaseblade, Blade of Grass and Fiery Greatsword can deal damage evenly if swung repeatedly at the long worm's arcing body. End-game weapons, like the Dark Lance and Night's Edge, can deal massive damage to multiple segments of the worm. By focusing attacks on the head, the next segment will already be weakened, likely falling in just one more hit. Because of the way the worm acts when its head is destroyed, it will quite literally feed itself into the meat grinder.

Dynamite will instantly kill any segments caught in its blast, providing an extremely fast (though extremely expensive) way to kill the Eater of Worlds. Grenades provide a more economical alternative, dealing high damage to several segments while also protecting the environment.

The choice of the weapon will essentially boil down to how safe you want play, or how fast you want to kill the Eater of Worlds.

Potions
Healing Potions are recommended, just in case you slip up and do manage to get hit by the Eater of Worlds. They do not have to be in the hotbar as they are easily accessed using the hotkey for healing (default is 'h'). Ironskin and Regeneration Potions can really help mitigate any hits you take. Hunter Potions can be very useful in spotting the Eater of Worlds as it burrows, making it easier to fight even without a raised platform.

The Thorns Potion will damage the Eater of Worlds every time it hurts you and is easy to craft.

Managing the Worms
Killing a segment of the Eater of Worlds will split it at that point into two worms, with a new Head and Tail forming on either side of the destroyed segment. Of course, the more worms there are, the harder it is to dodge their attacks. A fundamental strategy when killing the Eater of Worlds is correct management of each worm. Avoid splitting worms when you can. If there are little worms, concentrate on killing those first, before returning to the main worm.

Survival
Dying during a Worm fight will result in respawn at your spawn point. When you die, you will see the message "The Eater of Worlds has fled!" and you have to summon another in order to fight him again. However, all of the loot the sub-worms dropped will still be there, free for you to pick up.

Advanced Technique: "Surfing" the Worm
When using the above Platform scenario, and with proper movement, you can get the Eater of Worlds to chase you horizontally, as if it was surfing on your platform. This can be very useful once you are in the "Kill" phase of the fight, and to concentrate your fire on the Worms' Heads, which have less health than the Body. Using this strategy, entire sections of worms can be killed at once. The Ball 'O Hurt, Shurikens, or even a simple Gun, are all very effective. Note that it is much easier to get the Worm to surf by having a two Block wide platform.