How do I summon the Old One's Army event in Terraria?

To summon the Old One's Army event in Terraria, you need to interact with the Eternia Crystal Stand, which is the central mechanic of this event. The Old One's Army is a unique wave-based event that pits players against hordes of enemies, culminating in a battle against powerful bosses. This event is tied to the Tavernkeep NPC, who provides access to the Eternia Crystals and other related items. HereÔÇÖs a detailed guide on how to summon and prepare for the Old One's Army event.

First, you need to locate the Tavernkeep NPC. The Tavernkeep can be found as a bound NPC in the world after defeating the Eater of Worlds or Brain of Cthulhu. Once you free him, he will move into a suitable house if you have an available room. The Tavernkeep sells the Eternia Crystal Stand and Eternia Crystals, which are essential for summoning the event. The Eternia Crystal Stand costs 25 gold, and the Eternia Crystals cost 1 gold each. You will need at least one Eternia Crystal Stand and one Eternia Crystal to start the event.

To summon the Old One's Army, place the Eternia Crystal Stand in a flat, open area. The event requires a large space, so make sure the area is clear of obstacles and has enough room for combat. Once the stand is placed, interact with it and insert an Eternia Crystal. This will start the event, and waves of enemies will begin spawning. The event has three tiers of difficulty, depending on your progression in the game. Tier 1 is available after defeating the Eater of Worlds or Brain of Cthulhu, Tier 2 unlocks after defeating any mechanical boss, and Tier 3 becomes available after defeating Golem.

Preparation is key to surviving the Old One's Army event. Before starting, ensure you have strong armor, weapons, and accessories. The event is challenging, and the enemies become progressively tougher with each wave. For Tier 1, weapons like the Minishark or Demon Bow are effective, while Tier 2 and Tier 3 require more powerful gear like the Megashark or Terra Blade. Accessories that boost defense, damage, and mobility, such as the Obsidian Shield or Lightning Boots, are also recommended.

Building a proper arena can significantly improve your chances of success. Create a flat platform with enough space to move around and dodge attacks. Place walls or barriers to block enemy projectiles, but leave gaps for your own attacks. Adding heart lanterns, campfires, and honey pools can provide health regeneration and other buffs. If you have access to traps or explosives, you can set them up to deal additional damage to enemies.

During the event, focus on protecting the Eternia Crystal. If the crystal is destroyed, the event ends in failure. Prioritize enemies that target the crystal, such as the Dark Mages and Betsy in later tiers. Use crowd control weapons like the Star Cannon or Nimbus Rod to handle large groups of enemies. For Tier 3, the Betsy boss is particularly challenging, so make sure to have high-damage weapons and mobility accessories to avoid her attacks.

Common mistakes include underestimating the difficulty of the event and not preparing adequately. Make sure to stock up on healing potions, ammunition, and buffs like Ironskin and Regeneration. Another mistake is placing the Eternia Crystal Stand in a cramped area, which can make it difficult to maneuver and defend the crystal. Always choose a spacious, flat area for the event.

Advanced techniques include using sentries and summoning weapons to assist in combat. The Tavernkeep sells sentry summoning items, which can be placed to automatically attack enemies. Combining these with your own attacks can create a strong defense. Additionally, using mounts like the UFO Mount can provide mobility and allow you to focus on attacking without worrying about movement.

Resource requirements for the event include gold for purchasing the Eternia Crystal Stand and Crystals, as well as materials for building the arena and crafting potions. Make sure to gather enough resources beforehand to avoid running out during the event.

In terms of class and equipment considerations, melee characters should focus on high-defense armor and weapons with wide attack ranges, such as the Terra Blade. Ranged characters should use weapons with high damage output and accuracy, like the Megashark or Chlorophyte Shotbow. Mages can utilize spells like the Razorblade Typhoon or Golden Shower for crowd control, while summoners should rely on powerful minions like the Stardust Dragon.

Specific examples of successful strategies include using the Daedalus Stormbow with Holy Arrows for Tier 2, which can quickly clear waves of enemies. For Tier 3, the Solar Eruption is highly effective against Betsy due to its high damage and ability to hit multiple targets. Combining these strategies with proper arena setup and buffs will greatly increase your chances of success in the Old One's Army event.