The celebration of FGO's 5th anniversary in Japan has brought some gifts and quality of life changes we've come to expect by now, but the biggest impact by far was left by the newly released limited SSR Servant – Artoria Caster.

FGO's metagame has always revolved around consistent Noble Phantasm usage, since it represents the most reliable way of clearing content. Castoria definitely represents the natural evolution of that thought process – her skills provide a wide variety of buffs, whether it be to a single ally or to the entire team:

  • 20% attack up for her entire team – on par with Merlin, 10% less than Waver
  • 30% teamwide charge and 20% targeted – stronger than any other Servant
  • 50% arts up – on par with Tamamo-no-Mae
  • 30% NP gain up – 15% weaker than Nero Bride's 45%
  • 50% powermod against enemies classified as Threats to Humanity – a small niche, but not a bad thing to have

The charge she offers alone is enough to make her the new premier support, dethroning Waver from the position. 30% charge comes as a great boon for servants who have less than 30% charge themselves, such as Karna or Ozymandias. The other buffs she provides, however, elevate her into an amazing support for looping comps, as we will showcase in this article.

Finally, her Noble Phantasm offers another 30-50% Attack Up (depending on its rank), a debuff removal, as well as Special Invincibility. This new buff blocks the effects of Pierce Invincibility but does not block Instant Death effects (Chen Gong bypasses her invulnerability too), nor buff removals, so it's not an omnipotent tool as it may seem at first glance.

Since her release, many people have recorded various ways to clear content with her. We will note some, while a larger list can be found in our Discord server.

Summer Musashi(3-3-3) Berserker node

Salieri(3-3-3) Berserker node

Chen Gong(3-3-3) Rider node

Caster Gilgamesh(3-3-3) Berserker node

Jason(3-3-3) Lancer node

In case it hasn't been made clear, Caster Artoria enables a plethora of incredibly strong strategies, the most obvious being arts looping – clearing a node with only the usage of a single Servant's Noble Phantasm and Servant/Mystic Code skills. The main benefit of such setups is lower time investment, since they don't rely on Plugsuit. They are also a perfect choice for events thanks to the reliance on only one Servant's Noble Phantasm. That means most, if not all of the CE slots can be filled with event CEs.

With those concepts in mind, a large number of servants synergize well with Caster Artoria. Arts-based Noble Phantasms inherently have the best refund capabilities, and Castoria offers what the niche lacked – a single support with all of the buffs they required. However, some Servants are clear standouts. Particularly, due to her innate stats, damage and skills, we would like to single out Astarte.

The easiest way to showcase their synergy would be through a practical example.

We'll start with the most common type of farming nodes – three enemies in each wave. As an example, we will showcase the clear of the Ancient Bell of Tranquility farming node, Eight Gates Cave in Lostbelt 3.

Reasoning behind the example selection (click to expand)

One thing we should note about NP refund is that not all enemies will return the same amount of NP upon being hit. Specifically, Berserkers and Assassins return less than most classes (0.8× and 0.9× as much respectively), while Riders and Casters refund more (1.1x and 1.2x respectively).

Additionally, it's important to note the Overkill mechanic. With each hit from the Noble Phantasm that overkills the enemy, the NP charge gained is increased by half.

With that in mind, the most difficult nodes to loop on would be the ones where Astarte would have to deal neutral damage, while also having less innate refund. The obvious choice is, thus, a node with Assassin enemies.

For a more math-oriented overview of these mechanics, we suggest looking into the actual formula on which these calculations are based upon. You can find it in this blog post.

NP5 Astarte with no CE and double Castoria, Bell node
More detailed breakdown (click to expand) 3-3-3 Astarte Castoria

Since we're trying to showcase a stable clear, we won't be calculating the damage or refund with Astarte's 20% Arts Up on her third skill. Also, since damage can vary by ±10% due to the random modifier, we will use the lowest possible rolls in our calculations. Due to that, the damage and charge gained will differ slightly from the ones shown in the video.

Astarte gains a 20% modifier to her Noble Phantasm over each turn, which explains the increased damage between the first and second turn. We use the charging skills of only one of the Castorias in the first turn in order to keep the charges from the other for future turns. Astarte's third skill provides us with 50% charge in the first turn, bringing her to a total of 100%.

If we instead used the skills of both Castorias on the first turn, the charge gained from the NP would fall just under 100% total, even with Astarte's passive 3.5% charge added in. This might not be a problem when attacking different classes, but it forces us into this particular skill order here.

Even if the Astarte isn't NP5, she can refund. However, her damage may become a serious issue, gating her from being able to consistently clear some fights. To offer a clear comparison, we can showcase this in the following video of the same node.

NP1 Astarte with no CE and double Castoria, Bell node

It is very important to note that both of these clears were done without a CE on Astarte. This is to demonstrate that the clear could be done with any event CE, enabling setups with full event bonus lineups. If we used a Black Grail or Kaleidoscope, this would've been a trivial clear.

Finally, there has been an increasing number of nodes with partially filled waves – nodes which have only one or two enemies in some of the first two waves. Even in these situations, one could use Astarte with double Castoria to loop, with the assistance of an MLB Kaleidoscope. We offer a video of the Interstellar City: West node in Olympus, which drops Dawnlight Reactor Cores and Fruits of Longevity.

MLB Scope Astarte with Double Castoria, 1-1-2 node

FGO has been introducing increasingly stronger servants in the past few years, and Caster Artoria definitely exemplifies that design philosophy. Her kit is overloaded, and she is likely the single strongest support in the game at the time of writing.

All the videos included belong to their respective publishers.