Hey Terraria fans! Are you ready to take on the Old One's Army and score some serious loot? Well, you've come to the right place! In this guide, we're going to dive deep into creating the ultimate Old One's Army farm that will have you swimming in Defender Medals, powerful weapons, and armor sets. Forget struggling through each wave – with the right setup, you'll be laughing all the way to the bank! So, grab your pickaxe, summon your inner engineer, and let's get started!

Understanding the Old One's Army

Before we jump into building the perfect farm, let's quickly recap what the Old One's Army is all about. This event is triggered by placing an Eternia Crystal on an Eternia Crystal Stand. You can buy these items from the Tavernkeep NPC, who shows up after you've defeated the Eater of Worlds or Brain of Cthulhu. The Old One's Army is a multi-wave event where you defend the Eternia Crystal from hordes of enemies pouring in from portals. The difficulty and the rewards you get depend on the world's current progression – pre-Hardmode, early Hardmode, and post-Golem each have their own tiers.

Knowing your enemy is half the battle. The Old One's Army throws a variety of foes your way, each with their own strengths and weaknesses. You'll face basic goblins, kobolds, and orcs, but you'll also encounter tougher enemies like the Dark Mage, Ogre, Betsy (in the final tier), and flying wyverns. Understanding their attack patterns, weaknesses and how they move is essential for designing an effective farm. For example, the Dark Mage can cast powerful spells, so you'll want to take him out quickly. The Ogre, on the other hand, is a tanky melee enemy that can smash through defenses. Knowing these details will help you choose the right traps and strategies for your farm.

The rewards for completing the Old One's Army are well worth the effort. You'll earn Defender Medals, which you can exchange with the Tavernkeep for unique items like the Ballista Rod, Flameburst Rod, and Lightning Aura Rod. These sentry weapons are incredibly powerful and can be used to create even more effective farms or to bolster your defenses in other boss battles. You can also get armor sets like the Valhalla Knight and Squire armor, which provide significant boosts to your sentry damage and overall survivability. Plus, defeating Betsy in the final tier unlocks even more powerful weapons, such as the Betsy's Wrath.

Designing Your Old One's Army Farm

Okay, let's get down to the nitty-gritty of designing your Old One's Army farm. The key here is to create a setup that automatically eliminates enemies as quickly as possible, minimizing the risk to the Eternia Crystal and maximizing your loot. Here are some essential elements to consider:

• Location, Location, Location: The best spot for your farm is a large, flat area. This will give you plenty of room to build your defenses and maneuver around. Some players prefer building their farms in the sky to avoid ground-based enemies during other events, but this isn't strictly necessary for the Old One's Army. The most important thing is to ensure that the area is clear of any obstructions that might interfere with your traps or enemy pathing.
• The Arena: Your arena should be designed to funnel enemies into a kill zone. Start by creating a long, flat platform where the Eternia Crystal Stand will be placed. Then, build walls on either side of the platform to create a narrow corridor. This will force the enemies to walk through a concentrated area, making them easier to target with traps and sentries.
• Traps Galore: Traps are the backbone of any good Old One's Army farm. The most effective traps for this event are those that deal consistent damage over a wide area. Some excellent choices include Flame Traps, Super Dart Traps, and Lava Traps. Place these traps strategically along the corridor, ensuring that they cover as much area as possible. You can also use Conveyor Belts to push enemies into the traps, further increasing their effectiveness.
• Sentry Support: Don't forget about your sentries! The Ballista Rod, Flameburst Rod, and Lightning Aura Rod are all fantastic options for the Old One's Army. Place these sentries along the sides of the corridor, making sure they have a clear line of sight to the enemies. You can also use platforms to elevate your sentries, giving them a wider range of coverage. Experiment with different sentry placements to find what works best for your setup.
• Buffs and Potions: Don't underestimate the power of buffs and potions! Before starting the Old One's Army, make sure to drink a Wrath Potion and a Rage Potion to increase your damage output. A Lifeforce Potion can also be helpful for increasing your survivability. Additionally, consider setting up a camp near your farm with a Campfire and a Heart Lantern to provide passive health regeneration.

Essential Traps and Strategies

Let's break down some of the most effective traps and strategies you can use in your Old One's Army farm:

Flame Traps

Flame Traps are a classic choice for a reason. They deal consistent damage over a wide area and can quickly burn through hordes of enemies. Place them close together along the corridor to maximize their effectiveness. You can also use actuators to turn them on and off, allowing you to conserve mana if you're using a mana-intensive weapon.

Super Dart Traps

Super Dart Traps are another great option for dealing damage to multiple enemies at once. They have a long range and can pierce through multiple targets. Place them on platforms above the corridor to provide additional coverage. You can also use different types of darts, such as Poison Darts or Crystal Darts, to inflict additional effects on enemies.

Lava Traps

Lava Traps are a bit more risky, but they can be incredibly effective if used correctly. Place a thin layer of lava at the bottom of the corridor to deal continuous damage to enemies as they walk through it. Be careful not to place too much lava, as it can damage the Eternia Crystal. Also, make sure you have a way to quickly remove the lava if necessary.

Sentry Placement and Synergy

The placement of your sentries is crucial for maximizing their effectiveness. The Ballista Rod is great for dealing single-target damage to tougher enemies like the Dark Mage and Ogre. Place them near the entrance of the corridor to take out these enemies quickly. The Flameburst Rod is excellent for dealing area-of-effect damage to groups of enemies. Place them along the sides of the corridor to provide additional coverage. The Lightning Aura Rod is useful for stunning enemies and slowing them down. Place them near the Eternia Crystal to provide additional protection.

Experiment with different sentry combinations to find what works best for your playstyle and gear. Consider using the Squire armor to boost your sentry damage or the Valhalla Knight armor to increase your survivability. You can also use accessories like the Ogre Mask to further enhance your sentry damage.

Advanced Tips and Tricks

Ready to take your Old One's Army farm to the next level? Here are some advanced tips and tricks to help you maximize your efficiency and loot:

• The Power of Automation: Use actuators and timers to automate your traps and sentries. This will allow you to focus on other tasks, such as collecting loot or defending the Eternia Crystal from any stray enemies. You can also use logic gates to create more complex automation systems, such as turning off traps when there are no enemies nearby.
• Optimize for Enemy Pathing: Pay close attention to how enemies move through your farm. Identify any areas where they tend to get stuck or clump together. Adjust your trap placement and corridor design to optimize enemy pathing and ensure that they are always within range of your defenses.
• Loot Collection Strategies: Efficient loot collection is essential for maximizing your rewards. Use a gravitation potion to quickly move around the arena and collect any dropped items. You can also use a pet that automatically collects loot, such as the Faeling or the Lil' Eater. Alternatively, set up a series of hoppers and conveyor belts to automatically collect loot and deposit it into a chest.
• Dealing with Wyverns: Flying Wyverns can be a pain to deal with, as they can fly over your traps and attack the Eternia Crystal directly. Use ranged weapons or sentries with high vertical range to take them down quickly. You can also build a roof over your arena to prevent them from spawning inside.

Troubleshooting Common Issues

Even with the best-laid plans, things can sometimes go wrong. Here are some common issues you might encounter with your Old One's Army farm and how to fix them:

• Enemies are bypassing my traps: This is usually caused by gaps in your trap coverage or incorrect enemy pathing. Double-check your trap placement and corridor design to ensure that enemies are forced to walk through the kill zone. You can also use walls or blocks to redirect enemy movement.
• The Eternia Crystal is taking too much damage: This could be due to a lack of defenses near the crystal or enemies focusing their attacks on it. Place additional traps and sentries around the crystal to provide extra protection. You can also use a shield or a tanky summon to draw enemy aggro away from the crystal.
• I'm not getting enough Defender Medals: The number of Defender Medals you receive depends on the difficulty of the event and your performance. Make sure you're playing on the highest tier that you can handle and that you're effectively eliminating enemies. You can also increase your chances of getting more medals by using a Luck Potion or by playing with friends.

Final Thoughts

Building an effective Old One's Army farm in Terraria takes time and effort, but the rewards are well worth it. With the right design, traps, and strategies, you can easily defeat the event and earn a ton of Defender Medals and powerful gear. So, go forth, experiment with different setups, and have fun dominating the Old One's Army! Happy farming, Terrarians!