Percival

“An honorable knight, occasionally referred to as an unadulterated fool.”

Most of the time, if a person were to leave home and see their mother faint as they left, they would stop to check up on them. Not Percival, the fool who had to go out and slay his enemies as an AoE Arts Damage Dealer! No, not even the malicious Sir Kay could stop him from applying the beatdown!

In order to prove himself to the Fisher King, Percival has prided himself on becoming a powerful Arts Looper. Through the power of Protection of the Holy Grail A he has learned how to boost his own refund and cast multiple Noble Phantasms in a row which no enemy can avoid thanks to its Ignore Invincibility effect! And, true to the chivalry he learned under Gornemant, he will stand tall as a bastion for the team with Guardian Knight (Sacred Lance) B+ to serve as a meat shield for his allies. Of course, he’s not going to be foolhardy, having the Vermillion Armor of the Light of Salvation, giving him solid durability!

However extensive his deeds, aspects of Percival’s kit make him appear the fool. While Light of Salvation may protect him when coupled with Guardian Knight (Sacred Lance), the latter skill will lead to two turns of him taking all the hits unprotected. He also falls short in one of  his primary roles, where in looping situations, most of his skills wind up being irrelevant. He’s also on the weaker side of things thanks to low attack and no passive bonuses.

Percival may not have succeeded in asking the Fisher King about the Lance and the Grail, and failed to heal him, but he will still serve as a steady damage dealing tank for all who call upon him to serve. Yes, even if his FGO story is totally butchered from the original by Cretien de Troyes!

AoE Arts Looping

Like most Servants with two Castorias in a setup, Percival is capable of receiving a significant amount of refund from his Noble Phantasm against three-enemy waves. He can easily dish out damage with a Black Grail in hand and have enough in refund to continue to the next turn. He has great refund, even against Berserkers, refunding 80% each turn against a wave of 3. With his own charge and a mystic code boost to NP gain or arts, he can loop effectively against any 3-3-x node. To add to this as a benefit, his Noble Phantasm has the Ignore Invincibility effect which lasts the entire turn, making him reliable in practically all nodes to do damage.

Great Support

Percival’s invincibility is targetable and provides a bit of a heal, giving him the ability to protect another character at will. If that isn’t enough, he will also take the hits for them, having a three-turn target focus on his second skill. Then, any damage they’ve sustained can be healed through his Noble Phantasm.

Durable

Of course, if Percival applies his skills to himself, he becomes an incredibly durable Servant. He’s capable of negating a full turn of damage with the combination of target focus and invincibility, and has a fairly high HP pool to take the hits. With his Magic Resistance B++ passive, he’s also fairly resistant against Debuffs, making him hard to get rid of for the enemies.

Continued Target Focus

Target focus and invincibility can be a powerful combination, but Percival only gets 1 turn of invincibility compared to 3 turns of target focus. If he’s not careful, this can whittle down his HP pool in a hurry, even if facing his Class advantage.

Low NP Gain

Percival is the rare situation where an Arts Card times the number of Arts Hits is less than 2%. He is not going to refund his gauge outside of his Noble Phantasm and his skills easily. However, if he does not actually kill every enemy he comes across, his second skill provides a significant boost to his defensive NP gain, and may allow him to refill a significant part of his gauge every turn if the enemy has a high hit count.

Low Damage

Percival does not have a particularly high Attack stat, and does not have many ways of boosting it up. He only has one skill to boost his Arts and Noble Phantasm damage and the overcharge on his Noble Phantasm itself, leading to fairly poor damage overall compared to other options. The lack of a passive boost to his damage hurts even more.

When using Percival for looping, most Masters will want to avoid using Protection of the Holy Grail on the first turn. Against Berserker waves he will refund 80% without it, and use it on his second turn to fill in the remainder and boost his refund for the second wave. Guardian Knight and Light of Salvation tend to be used together, targeting Percival, allowing him to effectively negate an enemy’s damage for a turn by both taking all hits and negating them with invincibility.

• Protection of the Holy Grail A is Percival’s primary steroid, giving boosts to both NP Damage and Arts effectiveness. It also is crucial for looping thanks to the Arts boost as well as an extra 20% charge. Masters are going to want to use this turn two to enable looping capacity, or turn one if not looping. This skill should be the first to raise, but is actually optional to max as a Tropical Summer mystic code can provide the missing charge. That said, it is far easier to loop and opens up more mystic code options if it is maxed.
• Guardian Knight (Sacred Lance) gives Percival a target focus for three turns, along with a significant boost to his received damage NP gain. So long as there are enemies still alive after a wave and capable of attacking, this can result in substantial increases to NP gauge, with as little as a 3-hit enemy providing 54% of a bar in a turn. Against some Single Target enemy Servants, this could actually refill an entire gauge. Its leveling provides extra NP gain, so Masters planning to use him for these purposes could benefit from maxing the skill, but those just planning to use it for meatshield purposes can ignore it. This should be leveled second. 
• Light of Salvation B is Percival’s primary defense mechanism, giving Invincibility and HP boosts. Many Masters will use this on Percival himself as a protection for the first turn of his second skill. It can also be used to protect another ally if Percival is less important than them. As leveling it only provides more HP recovery, and the HP recovery is not too large, Masters may want to leave this skill alone. Level it last.

As with all Arts loopers, Percival is best used with an NP Damage Up CE to boost his general damage against enemy waves. His innate refund also makes him a good potential holder for Event CEs if he has the damage to clear the waves. If using him for defensive or support purposes, he should aim to use a Healing Power Up CE to recharge most of the lost health from each turn.

• The Black Grail: Percival has relatively low damage for his class and rarity, and boosting it can enable him to clear waves he’d otherwise be unable to. As he does not need starting NP gauge to loop, he can take advantage of its full benefit. In addition, as he has a low attack stat, this will add a significant percentage increase with its Attack stat bonuses. 
• Event CEs: Percival has amazing refund, capable of refunding off of even Berserkers, so if he does not need the damage he can easily hold an event CE or a bond up CE.
• Gentle Affection / Maid in Halloween / Street Choco-Maid / Sakura’s Special Bento: Percival has a significant heal on his Noble Phantasm and a less significant one on his third skill, so boosting these can negate the damage received from his second skill. Masters will need to decide if Percival or another Servant will receive more damage ahead of time, as some CEs only will boost the healing Percival receives, while others boost it for the full party.