What is the best way to defeat the Old One's Army event in Terraria?

The Old One's Army is a unique wave-based event in Terraria that requires careful preparation, strategy, and execution to defeat. This event is tied to the Tavernkeep NPC, who provides access to Defender Medals, which are used to purchase special sentry-based weapons and armor. The event consists of multiple waves of enemies, culminating in a boss fight against the Dark Mage and later the Ogre or Betsy, depending on the tier of the event. HereÔÇÖs a detailed guide on how to defeat the Old One's Army.

First, letÔÇÖs discuss the mechanics of the event. The Old One's Army is divided into tiers based on your progression in the game. Tier 1 is available after defeating the Eye of Cthulhu, Tier 2 after defeating any mechanical boss, and Tier 3 after defeating Golem. Each tier increases the difficulty, with stronger enemies and more waves. The event takes place at a designated Eternia Crystal Stand, which you must protect from enemies. If the crystal is destroyed, the event ends in failure. Waves progress automatically, and you must defeat all enemies in a wave to advance to the next one.

Preparation is key to succeeding in the Old One's Army. Start by building a proper arena. The arena should be flat and wide, with platforms or blocks to help you maneuver. Place walls or barriers on either side of the crystal to funnel enemies into a central area where you can focus your attacks. Use traps like spiky balls or dart traps to deal passive damage to enemies. Additionally, set up heart lanterns, campfires, and honey pools for regeneration. Buff stations like the Bast Statue and Sharpening Station can also provide useful bonuses.

For equipment, your class choice will influence your strategy. Melee builds can use high-damage weapons like the Terra Blade or Influx Waver, along with armor like Beetle or Turtle Armor for defense. Ranged builds should opt for weapons like the Megashark or Tsunami, paired with Shroomite Armor for maximum damage output. Magic users can rely on weapons like the Razorblade Typhoon or Nebula Blaze, with Spectre Armor for healing or damage. Summoners should use powerful minions like the Stardust Dragon or Terraprisma, along with Tiki or Spooky Armor. Regardless of your class, accessories like the Celestial Shell, Ankh Shield, and Wings are essential for mobility and survivability.

During the event, focus on crowd control and prioritizing high-threat enemies. Use sentries like the Ballista or Flameburst Turret to deal consistent damage to waves of enemies. These sentries are purchased from the Tavernkeep using Defender Medals. Place them strategically to cover multiple lanes. For Tier 3, the Lightning Aura sentry is particularly effective against flying enemies like Wyverns and Betsy. Use your main weapon to target stronger enemies like Dark Mages or Ogres, while letting your sentries handle smaller mobs.

Buff potions are crucial for success. Use Ironskin, Regeneration, and Endurance potions to boost your survivability. Damage-boosting potions like Wrath, Rage, and Magic Power can significantly increase your DPS. Swiftness potions help with mobility, while Summoning potions increase the number of minions you can deploy. Food items like Pumpkin Pie or Seafood Dinner provide additional stat boosts.

One common mistake is neglecting the crystalÔÇÖs health. Always keep an eye on the crystalÔÇÖs HP and prioritize enemies that are targeting it. Another mistake is underestimating the importance of sentries. Sentries are your primary source of damage in this event, so upgrade them as soon as possible using Defender Medals. Avoid spreading yourself too thin by trying to cover too many areas at once. Focus on controlling a central zone and let your sentries handle the rest.

Advanced techniques include using teleporters to quickly move between lanes or setting up lava traps to deal passive damage. For Tier 3, consider using the Rod of Discord to dodge attacks from Betsy or the Ogre. Optimize your sentry placement by testing different configurations during practice runs. For example, placing Flameburst Turrets on elevated platforms can help them target flying enemies more effectively.

Resource requirements include Defender Medals for purchasing sentries and upgrades, as well as materials for potions and arena construction. Farm Defender Medals by completing lower-tier events before attempting higher tiers. Gather materials for potions by exploring biomes and fishing. For arena construction, stock up on blocks, traps, and wiring components.

In summary, defeating the Old One's Army requires a combination of preparation, strategy, and execution. Build a well-designed arena, equip yourself with the best gear for your class, and use sentries effectively. Prioritize high-threat enemies, manage your resources wisely, and avoid common mistakes like neglecting the crystal or underestimating sentries. With practice and the right approach, you can conquer this challenging event and reap the rewards.