How do I create a base that is safe from Old One's Army events in Terraria?

To create a base that is safe from the Old One's Army events in Terraria, you need to understand the mechanics of the event and how it interacts with your base. The Old One's Army is a wave-based event triggered by placing an Eternia Crystal Stand and an Eternia Crystal. The event spawns enemies that attack in waves, with the goal of destroying the crystal. If the crystal is destroyed, the event ends in failure. To protect your base from this event, you need to ensure that the event does not interfere with your main living area or storage.

First, you need to understand the mechanics of the Old One's Army event. The event is centered around the Eternia Crystal Stand, which must be placed on a flat surface. The enemies spawn from portals on either side of the stand and will move toward the crystal to attack it. The event can be triggered in any biome, but the difficulty and enemy types vary depending on the game's progression (pre-Hardmode, Hardmode, or post-Plantera). To keep your base safe, you should build the Eternia Crystal Stand and the event arena far away from your main base. This ensures that the enemies spawned during the event do not wander into your living area or storage rooms.

To set up a safe base, follow these steps. First, choose a location far from your main base. This could be in a different biome or on the opposite side of the world. The area should be flat and wide enough to accommodate the event arena. Next, build a platform for the Eternia Crystal Stand. The platform should be at least 60 blocks wide to give you enough space to fight the enemies. You can use platforms or solid blocks for the floor, but make sure the stand is placed on a solid block. Surround the stand with walls or barriers to prevent enemies from reaching it too quickly. You can also add traps, such as dart traps or flame traps, to help defend the crystal.

When building the arena, consider adding layers of platforms above the ground level. This gives you more space to move and attack enemies from different angles. You can also add heart statues or star statues connected to timers to provide health and mana regeneration during the event. Additionally, place campfires and heart lanterns around the arena to boost your health regeneration. If you have access to them, honey pools and bast statues can further increase your survivability.

One important tip is to avoid placing the Eternia Crystal Stand near your NPC housing. NPCs can be killed by the event enemies, and their deaths can disrupt your base's functionality. Keep the event arena isolated from your main base to prevent this. Another tip is to use summoner weapons or sentries to help defend the crystal. These can attack enemies automatically, giving you more time to focus on the stronger waves.

Common mistakes to avoid include placing the Eternia Crystal Stand too close to your base, not building a wide enough arena, and neglecting to add defensive traps or buffs. These mistakes can make the event much harder and risk your base being overrun by enemies. Always plan your arena carefully and test it before starting the event.

For advanced techniques, consider using teleporters to quickly move between different parts of the arena. This can help you respond to threats more efficiently. You can also use actuators to create temporary barriers that block enemy movement. Additionally, if you have access to endgame gear, such as the Zenith or Terraprisma, you can use these powerful weapons to quickly defeat the event waves.

Resource requirements for building a safe base and arena include a variety of blocks, platforms, traps, and furniture. You will need at least 60 blocks for the arena floor, as well as materials for walls, platforms, and traps. Heart statues, star statues, campfires, and heart lanterns are also essential for boosting your survivability. If you plan to use teleporters, you will need wire, switches, and actuators.

Class and equipment considerations depend on your preferred playstyle. Melee characters should focus on high-defense armor and weapons with wide attack ranges, such as the Terra Blade or Solar Eruption. Ranged characters can use weapons like the Megashark or Tsunami with appropriate ammunition. Mages should use weapons like the Razorblade Typhoon or Nebula Blaze, while summoners can rely on powerful minions like the Stardust Dragon or Terraprisma. Regardless of your class, make sure to equip accessories that boost your damage, defense, and mobility.

In summary, creating a base that is safe from the Old One's Army event involves building a dedicated arena far from your main base, setting up defensive structures and traps, and equipping yourself with the right gear. By following these steps and avoiding common mistakes, you can protect your base and successfully complete the event.