What is the best weapon to use against the Old One's Army in Terraria?

The Old One's Army is a unique event in Terraria that requires careful preparation and strategy to succeed. This event involves defending the Eternia Crystal from waves of enemies, including powerful bosses like Betsy in the later tiers. To effectively tackle this event, you need to understand the mechanics, choose the right weapons, and prepare your character and arena properly.

First, let's discuss the mechanics of the Old One's Army. The event consists of multiple waves of enemies that spawn from portals on either side of the Eternia Crystal. Your goal is to protect the crystal from being destroyed by these enemies. The event has three tiers, with each tier increasing in difficulty. Tier 1 is accessible after defeating the Eyre or Brain of Cthulhu, Tier 2 after defeating any mechanical boss, and Tier 3 after defeating Golem. Each tier introduces stronger enemies and bosses, requiring better gear and strategies.

To prepare for the Old One's Army, you need to focus on both your character's equipment and the arena setup. For your character, the best weapon choice depends on your preferred class. Melee users should consider weapons like the Terra Blade or the Influx Waver, which offer high damage and good crowd control. Ranged players can use the Tsunami or the Phantasm, both of which are excellent for dealing with multiple enemies. Magic users should opt for the Razorblade Typhoon or the Lunar Flare, which provide high damage and area-of-effect capabilities. Summoners can use the Stardust Dragon or the Xeno Staff, which are effective at dealing with large groups of enemies.

In terms of armor, you should wear the best available for your class. For melee, this could be the Beetle Armor or the Solar Flare Armor. Ranged users should consider the Shroomite Armor, while magic users can benefit from the Spectre Armor. Summoners should aim for the Stardust Armor. Accessories should focus on increasing your damage output and survivability. Items like the Celestial Shell, Warrior Emblem, and Avenger Emblem are excellent choices. Don't forget to use buff potions like Ironskin, Regeneration, and Endurance to further enhance your performance.

The arena setup is crucial for success in the Old One's Army. You should create a flat area with platforms at different heights to allow for mobility and better targeting of enemies. Place traps like Dart Traps and Flame Traps to deal additional damage to incoming enemies. Heart Lanterns and Campfires can provide health regeneration, while Bast Statues can increase your defense. Make sure to have a pool of honey nearby for an additional regeneration boost.

During the event, focus on prioritizing high-threat enemies like the Dark Mages and Betsy. Use your weapons' area-of-effect capabilities to deal with groups of smaller enemies. Keep an eye on the Eternia Crystal's health and be ready to repair it if necessary. Positioning is key; try to stay in the middle of the arena to respond quickly to threats from either side.

Common mistakes to avoid include neglecting to repair the Eternia Crystal, not using buff potions, and failing to prioritize high-threat enemies. Additionally, not having a well-prepared arena can make the event much more difficult. Make sure to test your setup before starting the event to ensure everything is in place.

Advanced techniques include using the Nurse NPC to heal during the event, setting up teleporters for quick movement across the arena, and using the Rod of Discord to dodge attacks. These strategies can give you an edge in the later, more challenging waves.

Resource requirements for the Old One's Army include a variety of materials for crafting weapons, armor, and potions. You will also need Eternia Crystals to start the event, which can be purchased from the Tavernkeep NPC. Make sure to gather enough resources beforehand to avoid running out during the event.

In summary, succeeding in the Old One's Army requires careful preparation, the right equipment, and a well-designed arena. Focus on your character's strengths, use buff potions, and prioritize high-threat enemies. With the right strategy, you can defend the Eternia Crystal and emerge victorious.