FGO 3-Turn Farming Meta Guide: Castoria, Koyanskaya & Oberon

Farming is a huge part of Fate/Grand Order (FGO). Event shops, Lottery events, Free Quests, and high-HP 90+ and 90++ nodes can require hundreds of clears, so shaving a fight down to three turns makes a noticeable difference over time.

The most efficient setups revolve around matching your damage dealer to the right support system. Altria Caster (Castoria) enables Arts looping through NP refund, Koyanskaya of Light turns Buster Servants with suitable batteries into three-turn farmers, and Oberon provides the enormous final-wave damage boost needed for high-HP enemies.

This guide explains the requirements behind these systems, the role of each support, and the basic rotations you can adapt to different farming nodes.

What You Need for Consistent 3-Turn Farming

A three-turn setup is only reliable when the Servant, supports, Craft Essence, and node all fit together. Copying a team without checking those details is one of the easiest ways to end up one NP short on Wave 2 or 3.

Max the Important Support Skills

The most important support skills should generally be taken to 10/10/10. This is especially important when your rotation depends on exact NP charge amounts, cooldown reductions, or maximum-card buffs.

Your DPS Has Requirements Too

The damage dealer is just as important as the support. For Koyanskaya-based Buster farming, the key requirement is usually a self-charge skill that can be used again after the double cooldown reduction. Servants with an appropriate battery and cooldown can loop even when their NP itself provides no refund.

Your Servant may also require Append Skill 2 (Mana Loading). At Level 10, it provides 20% starting NP gauge, which can turn a 30% self-charge into a workable setup with a suitable starting-NP Craft Essence. The exact requirement depends on the Servant, starting NP on the CE, and the node’s enemy count.

Check the Enemy Formation

There is no universal three-turn rotation. Arts looping is especially comfortable against three-enemy waves, because more targets generally mean more opportunities for NP refund. Buster setups don’t rely on NP refund and are therefore better suited to irregular formations such as 1/1/1 or 2/1/3, assuming the Servant has enough charge and damage. 

1. Arts Farming: Double Castoria

The Double Castoria system is built around Arts NP refund. Instead of relying entirely on fixed NP batteries, your damage dealer recovers NP after each Noble Phantasm and uses that refund to reach the next one. This setup is best for three-enemy waves and Arts AoE Servants with strong NP refund.

Standard Team

• Frontline: Arts AoE DPS / Altria Caster / Altria Caster
• Backline: Flexible support, often Oberon, Waver, or another utility option

The exact setup varies by Servant. Some farmers need additional charging, while others can reach the required refund with only the two Castorias.

Craft Essence Choices

For maximum damage, The Black Grail is a natural choice when the team can provide enough NP charge without a starting-NP effect. A starting-NP CE is more convenient when your damage dealer needs extra charge to reach 100% at the beginning of the rotation. The ideal CE is determined by the DPS’s battery and refund rather than by damage alone.

Arts Loop Rotation

Turn 1: Establish the Refund

Use the required Castoria buffs, including Arts and NP-generation support, then activate any necessary self-buffs on your DPS. Fire the first NP and check the resulting refund. Your target isn’t simply “100% refund.” The required number depends on the Servant’s battery, Craft Essence, enemy count, overkill, and support setup.

Turn 2: Refill and Fire Again

Use the remaining Castoria charge tools to bring the DPS back to the required NP threshold. Once the gauge is ready, launch the second NP. If your refund falls short here, the problem may be insufficient enemy count, low NP level, missing NP-generation buffs, or simply a mismatch between the Servant and node.

Turn 3: Finish the Highest-HP Wave

Use your remaining offensive buffs and charge effects. If you need more damage for the final wave, an Order Change can bring Oberon into the frontline. Oberon’s NP Damage support can turn the final NP into a much stronger finishing attack, making this version of the Arts setup very useful for high-HP final waves.

2. Buster Farming: Double Koyanskaya + Oberon

Buster NPs generally don’t provide the same NP refund engine as Arts NPs. Instead, the Double Koyanskaya system works by repeatedly charging the DPS while reducing the cooldown of its own battery skill. This is what allows an eligible Buster Servant to use its self-charge more than once during a three-turn run. This setup is best for 90+ and 90++ configurations where an Arts farmer may struggle to generate enough refund.

Standard Team

• Frontline: Buster AoE DPS / Koyanskaya of Light / Koyanskaya of Light
• Backline: Oberon

A Chaldea Combat Uniform or another Mystic Code with Order Change is commonly used when Oberon needs to enter on the final wave.

Buster Requirements

A typical farmer needs a self-NP battery with an appropriate cooldown. Koyanskaya’s first skill provides 50% NP charge and reduces an ally’s skill cooldown by two turns, so using it twice creates the cooldown reduction needed to bring a qualifying battery back online.

A starting-NP CE or Level 10 Mana Loading may also be necessary to reach the first NP. The exact configuration depends on whether the DPS has a 30% or 50% battery and how long that battery’s cooldown is.

Standard Buster Rotation

Turn 1: Start the Engine

Get your DPS to the required starting NP threshold. Use the appropriate Buster-support skills and fire the first NP. Save the cooldown-reduction batteries for the part of the rotation where they are needed to set up the later turns.

Turn 2: Double Koyanskaya Charge

Use Koyanskaya’s NP batteries on the DPS. These also reduce the relevant skill cooldowns, setting up the second NP while preparing the DPS’s own battery for reuse. Fire the second NP once the gauge is filled.

Turn 3: Bring in Oberon

Use Order Change to bring Oberon forward if your setup requires it. Re-use the DPS’s battery once its cooldown has been restored, then apply Oberon’s NP charge and damage buffs. Finish with the third NP.

This rotation can support surprisingly large final-wave damage, which is why the Koyanskaya + Oberon combination remains one of the defining Buster farming frameworks.

How to Choose Between Castoria and Koyanskaya

You don’t need to choose one system permanently. In fact, you should aim to access more than one farming engine because event nodes can vary dramatically.

6-CE Farming: What Makes It Difficult?

Farming with six Event Craft Essences is attractive because it maximizes event drops, but it removes many of the free starting-NP options that make looping easier. That is where things like Mana Loading, self-battery skills, cooldown reduction, and powerful supports become important.

A DPS with a suitable starting gauge from Append Skill 2 can sometimes replace a starting-NP CE, allowing all six CE slots to be devoted to the event bonus. However, 6-CE farming is not automatically better for every Servant. If forcing the setup requires awkward face-card RNG or unreliable refund, a simpler five-CE setup may save more time in practice.

Troubleshooting a Failed 3-Turn Loop

• Wave 1 Works, Wave 2 Fails: Your refund may be too low. Check the enemy count, overkill timing, NP level, NP-generation buffs, and whether the support skills are fully upgraded.
• Wave 3 Has Enough NP but Not Enough Damage: The problem is probably damage rather than looping. Try stronger offensive buffs, a higher-quality CE, or Oberon for the final-wave burst.
• The DPS Is Always Short at the Start: Check Mana Loading, starting-NP effects from your CE, and the Servant’s own battery. A missing 10–20% at the beginning can prevent an otherwise workable rotation from functioning.
• The Setup Requires Too Much RNG: A theoretical three-turn clear isn’t necessarily a good farming team if you constantly need specific command cards or lucky refunds. For repeated farming, consistency should matter more.

The three-turn farming meta in FGO is built around solving one fundamental problem: how do you fire your damage dealer’s NP three times without wasting turns?

Castoria solves that problem through Arts NP refund. Koyanskaya of Light approaches it from the opposite direction, using NP batteries and cooldown reduction to make Buster batteries reusable. Oberon then provides the enormous final-wave damage increase needed when ordinary looping damage isn’t enough.

The best setup depends on your DPS and the node in front of you. Three-enemy formations often favor Arts looping, while irregular waves and high-HP finales can make Buster setups more attractive. Once you understand the charge requirements, cooldowns, refund thresholds, and final-wave damage needs, you can adapt these systems to a much wider range of farming stages.

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