Archetype Earth

Arcueid benefits extremely well from skill levels as she is often paired with Koyanskaya of Light and/or a Cooldown Reduction Mystic Code. Furthermore, all the relevant effects of her skill set scales well with levels, particularly her second skill.

• Rainbow Mystic Eyes A - Both the Attack buffs and Defense debuff scale with level so it is beneficial to raise this skill. At level 10 she can use this twice in 3 turns with the Double Koyanskaya setup, basically granting her a 60% Attack buff for the third wave in farming situations.
• Breath of the Planet C  – By far her strongest and most impactful skill, maxing this is tantamount to her functionality. Without the maxed NP Charge and lowered cooldown to combo with Double Koyan + Atlas Academy or Plugsuit Oberon setup, she cannot be played as an omnifarmer well. 
• Funny Vamp EX – Of her three skills, this is perhaps the one that benefits the least from raising its level, but it is still a very worthwhile skill to raise  as the NP Charge effect that she grants to teammates scales with its level.

“Resign yourself. You cannot escape. My grasp is with the breath of the planet.”

The White Princess of Crimson Moon and the titular heroine of Tsukihime, Archetype: Earth or more endearingly called Arc or Arcueid Brunestud, is one of the most anticipated arrivals of Type-Moon characters into the Grand Order universe. True to her unfathomable might and destructive capacity, Archetype: Earth is a potent offensive AoE-Buster Servant with several powerful teamwide support effects at her disposal.

To speak of Arc, we must first speak of her Noble Phantasm. Her signature move, or more colloquially known as the Marble Phantasm, brings the true ancestor castle into the fold - the Brunestud Millennium Castle. Outside of being a powerful AoE nuke that deals extra damage to all Chaotic alignment enemies, it also charges the NP Gauge of all [Living Human] aka [Pseudoservant] allies by a sizable amount and changes the battlefield to the unique [Millenium Castle] battlefield for 3 turns before dealing damage. The last effect is important for two of her other effects: one is her unique passive Original D that gives a 30% boost to all her card types while the Castle is on the field, and the other effect is in her third skill. 

Befitting her status, Arc has a skill set with multitude of powerful effects bundled in that make even the most modern Servants envious. Rainbow Mystic Eyes A is a combination of personal Attack boost, teamwide Defense Debuff and teamwide Skill Seal. Straightforward, but effective. Breath of the Planet C is easily one of if not the strongest personal NP Charge skills in the game, giving her a whopping 100% NP Gauge at max level and a NP Damage boost as well to compliment it. Funny Vamp EX - her joke skill from Fate/Extra - grants a partywide Invulnerability buff for 1 time over 3 turns, a party wide Buff Removal Resistance buff, and most importantly, a 30% NP Gauge charge for all teammates except Arc while the Millenium Castle is on the field.

From a Buster Looping perspective, Arc is already a very powerful Servant with a combination of fantastic NP Charge and strong personal buffs.. Her capacity to farm with Black Grail as a Buster Looper already makes her exceptional compared to most of her peers. On top of that, providing NP Gauge charge for teammates as a looper is invaluable, and one of the reasons why some Servants like Taigong Wang have so much versatility and staying power in various team setups. But even outside of farming, Arc provides several good utility effects to her team for harder content as well, ranging from Buff Removal Resistance, Skill Seal, Defense Debuff, teamwide Invincibility, and as mentioned before, teamwide NP Charge. 

On the other hand, she is fundamentally a very expensive Servant to reach the level of comfort that one desires from an Omnifarmer. Arc’s biggest problem is her Class. Moon Cancer is a really poor class, if not the worst in terms of coverage, which significantly lowers her damage floor. While Arc’s damage is good, at a low to medium investment level (no Black Grail, NP Level 1, not owning both Koyanskaya of Light and Oberon) she will feel quite underwhelming to use, and will struggle in a lot of nodes with one huge HP enemy that many future events will have. She has one of the biggest jumps in comfort-of-use from base to NP Level 2 due to this, as it gives her just enough firepower to truly break away and become the top tier Servant that she wants to be, but that is by no means necessary for her to shine.

Exceptional NP Charging Capacity

Having one of the strongest NP Charge skills in the game makes Arc really well-suited for farming and lets her use a plethora of powerful Craft Essences with impunity. However, that is not even touching on her capacity to charge teammates’ NP Gauge as well via her Noble Phantasm and third skills. While both of those effects are conditional, they are extremely impactful when triggered. 

Powerful Wave Clearing Potential

Arc has a hard hitting AoE Buster Noble Phantasm and can abuse the Double Koyanskaya / Oberon setup very easily thanks to her NP Charge skill. Even outside of the traditional Double Koyanskaya system, she makes for a very strong multi-core farmer as she can easily handle the weaker waves while giving NP Gauge to the stronger damage dealers in the team to handle the other waves. 

Strong Utility For Challenge Quests

Skill Seal, Defense Debuff, Invulnerability and Buff Removal Resistance are all fantastic tools for Challenge Quests, allowing Arc to be a very versatile unit for any roster.

Expensive To Reach Full Potential

Due to her class having essentially zero class advantage damage bonus and no NP Upgrade Interlude yet, Arc’s NP Damage at NP Level 1 may not be enough to clear some irregular nodes with one particularly high HP in farming situations. Arc will also feel quite underwhelming without some of her optimal setup such as Black Grail, Koyanskaya of Light, or Oberon, as all of them have such a strong amplification effect on her damage output overall.

Unlike most Buster AoE farmers, Arc does not need a NP Charge Craft Essence and is fully capable of farming without any, provided the right combination of setup and Mystic Code is provided. Thus, firepower should be her biggest priority when picking Craft Essences. Since she has all three of Attack, Card Performance Boost and NP Damage in her kit, any of these effects will be equally good as damage boosting effects that she can pick. However, that does not mean Starting NP Gauge can’t be great for her. In some Multi-cores setup  where one can save her second skill for wave 2, then Starting NP Gauge + another teamwide NP Gauge and second Append skill can get two NPs to handle two weaker waves. NP Overcharge can be situationally useful if she is used with [Living Human] / [Pseudoservant] teammates like Zhuge Liang or Sima Yi in the team. 

• The Black Grail / Heaven’s Feel / Corrupting Mud Rain: This should be the default Craft Essence choice for end game Arcueid as they offer the biggest powerboost to her and she doesn’t suffer any huge downside from it. 
• Blue Illusion / Poolside Bar / Holy King of Twilight / Duke of Flame / Demon King of the Sixth Heaven / Hero Elly's Adventure: These are great alternatives for Arc in the meantime if Master manages to get them before getting her better options.
• Kaleidoscope / Aerial Drive / First Day of Filming: Good Starting NP Gauge Craft Essences that can be combined with her second append skill and teammates’ NP Charge to ensure a minimum of two NPs fired off, and saves some further NP Charge for latter waves.