Mordred (Rider)

"F-father?! I, no, this isn't Prydwen. It's just...a similar looking Noble Phantasm."

The Knight of Treachery (swimsuit edition) is an Arts AoE Rider with one intensive focus - Constant AoE NP spam.

While her base NP gain is somewhat low compared to the average for a servant with two 2-hit Arts cards, she more than compensates for it with the various Arts boosts provided by her kit, an NP gauge increase skill, and, most importantly, good hit counts on her NP. All these factors together allow Mordred Rider to receive a 43% NP gauge refund from her own kit when hitting a normal full 3 enemy wave with her NP, and even more with team assistance or an NPAA chain.

Mordred’s new look doesn’t end there, with two solid durability skills to keep her consistently on the field, and a little niche star generation buff to make her Arts-focused chains actually provide stars as well for further NP spamming. Still, unlocking her full NP spamming potential requires extensive Arts support and sufficient enemies to attack. Even then, her sheer burst damage is generally quite a bit lower than her peers. 

Regardless, while Mordred Rider ultimately falls down to being a one-trick pony who relies on having 3 foes to constantly blast with Prydwen, she does it so incredibly well that it forces her into a powerful position for any Arts team.

Mordred is one of the prime candidates for 3-turn farming via Arts NP looping. However, creating a 3-turn looping team from scratch can be tricky, especially if options are limited. Masters can use the Command Chain Calculator tool to try and create an NP looping team, but the key points are:

• A Quick or Arts NP must have both a good base NP Gain and a good hit count.
• Card Performance buffs and NP Gain buffs stack multiplicatively, each enhancing the effect of the other. For ideal NP looping, Masters tend to stack both buffs.
• Overkill helps a fair bit, boosting the refund potential of each affected hit. Stronger Noble Phantasms trigger Overkill earlier, thus granting more refund potential. Masters can also soften a mob's HP to more easily trigger Overkill before an NP by putting the NP later in the Attack chain. 
• Generally, Starting NP Gauge is essential to kickstart the first NP, while NP charging can enable different CE choices or cover missing NP Bar percentages mid-fight. 
• Lastly, the amount, HP and class of the enemy is important, with certain classes granting more or less NP Gain upon being attacked. Berserkers notably only grant 0.8x of the normal NP Gain to your Servants, while Casters grant 1.2x of the normal NP Gain to Servants upon being attacked. 

Incredible NP Spam Power

Mordred Rider arguably has some of the best Arts NP spam in the game if she can get the right conditions, being able to completely refund her gauge back to 100% with her own kit and a solid NPQA or NPAA chain. She can manage more or less the same without any real assistance from her own cards if she has a combination of massive Arts or NP Gain buffs from Servants such as Tamamo, Nero (Bride) or a post Rank-Up Paracelsus. While the damage output of her NP isn’t spectacular in a single instance, the fact each one tends to lead into another very easily makes it more powerful than it initially appears. Most AoE NPs out-damage Mordred Rider’s, but few can so easily NP twice in succession like her's can.

High Durability

With both an Evasion from Rodeo Flip and a guts from Endless Summer, Mordred Rider has no issues enduring the more threatening attacks she may face on a sortie. While both skills are on an absurd skill cooldown of 9 turns at base, most battles struggle to last long enough for them to come back off cooldown without using a stalling team (which, admittedly, Mordred Rider has good synergy with), so it isn’t as terrible as it may seem. She can endure any NP thrown at her, even if it has inherent Incinvibility Pierce, making her a very consistent damage dealer.

Stall Team Synergy

Prydwen Tube Riding packs a handy, while inconsistent, chance to reduce the NP gauge of every enemy hit by it, with the chance scaling with overcharge. This, combined with Mordred Rider’s Arts card focus and strong durability, makes her an excellent contributor to stalling teams, especially those facing off waves of 3 powerful servants with threatening NP gauges. The 50% chance to get the NP gauge drop may not be reliable, but all RNG falls to consistency, and Mordred Rider can absolutely manage to chain multiple NPs in the same battle consistently. As such, she remains a powerful damage dealing pick with some unique stalling power on the side.

Dependance on Team Composition

In order to be able to do back-to-back NPs without getting an NPAA chain, Mordred Rider needs crits. To get back-to-back NPs without Crits, she needs Arts and/or NP Gain buffs. The point being, Mordred Rider ultimately needs something she can’t provide for herself if she wants to be able to NP spam consistently, since banking on drawing an NPAA chain is hardly reliable. As a result, she usually needs one, if not both, of her teammates to provide a supportive tool to her in some way, whether it’s NP gauge chargers from Waver, Arts buffs from Tamamo or critical stars from any sort of star generator. While Mordred technically performs fine solo, her performance with 2 teammates who don’t provide anything to her and steal both her card spots and critical stars isn’t so good.

Mediocre Raw Damage

Mordred Rider, while packing some offensive buffs to aid her damage output, still isn’t a force of nature in terms of raw high NP damage. Her kit certainly attempts to compensate for it with how easy it is to spam her NP, but sometimes one only has the resources or turns to get one NP off, and Masters want it to hit as hard as humanly possible. In both ST and AoE situations, Mordred Rider gets outclassed by competitors. While she still has impressive regular Arts card damage due to her Arts buff’s 3 turn duration, it doesn’t really tend to compensate for the vast gap in NP damage output.

Farming Potential Limited at Lower NP Levels

Refunding Mordred's entire NP Bar is easier if Overkill is triggered after the first few hits. However, even with extensive support the lower level Mordred's Noble Phantasm is, the harder it is to clear the wave at all, let alone make use of Overkill in assisting a full NP refund. In effect, Mordred (Rider)'s farming power is greatly improved with additional copies. 

Mordred (Rider) is primarily used for her farming potential, but Masters may find her AoE stalling useful for a few challenging AoE encounters as well. Either way, boosting her damage output and refund potential first is ideal, and Masters need to fully invest and maximize Cerulean Ride to be able to hit the damage and refund benchmarks necessary to pull of any NP looping. 

• Cerulean Ride is the most important part of Rider Mordred’s kit, increasing both her damage output and NP gain. Max this first, and do so as soon as possible to start experimenting will full NP looping. 
• Leveling Rodeo Flip may be good if you wish to keep her Evasion on a lower cooldown as well as produce more stars on her NP, but generally it's survival aspect forces it to be timed for a dangerous enemy turn while its already carrying a significant base cooldown. Thus, most of its benefits from leveling are redundant and Masters can level it last, especially as it tends to go unused during farming. 
• Endless Summer doesn’t have an improvement in the Guts buff from leveling, but it does gain a slight improvement in the NP gauge increase per level. Hitting the benchmark of 30% can enable some great synergy with certain hybrid CEs and additional 20% NP Batteries. Thus, level this second. 

To enable Mordred (Rider)'s NP spam, Masters need either Starting NP Gauge to jumpstart her first NP, Arts Performance Up for striking a balance between NP refunding and damage, and/or NP Gain Up to vastly boost her NP refunding as it stacks multiplicatively with Mordred's own Arts buffs. Masters can also aim to simply improve her damage output, for which both Attack Up and NP Damage Up work well. 

• Kaleidoscope / The Imaginary Element (Limit Broken) - Mordred Rider packs a small NP gauge charger, allowing her to immediately NP when using these two CEs without any external support. If she has sufficient support from an allied Nero Bride or Tamamo this is an effective option, as Mordred Rider can immediately wipe out the first wave she comes across and then quickly charge up the next NP for good measure. Naturally, this is also her first pick for QP and EXP farming, as damage isn’t exactly a priority so long as you meet the damage benchmarks.
• Formal Craft / Cute Orangette / Divine Banquet / Repeat Magic (Limit Broken) - While these options provide different stats, their goal is the same for Mordred’s kit - provide as much NP spam as possible. Repeat Magic also has the added bonus of a small NP gauge charge, letting Mordred Rider get up to 100% with Endless Summer and a Waver on turn 1, while still reaping the benefits of a low-cost CE.
• Golden Sumo / Little Halloween Devil / Magical Girl of Sapphire / Holy Night Supper / Grand Puppeteer - If Rider Mordred wants to NP early on but still get some side benefits, then these are the CEs of choice. Golden Sumo and Holy Night Supper improve Mordred’s damage output significantly while still helping her get that first NP off. Meanwhile Little Halloween Devil and Grand Puppeteer hope to close things out hard and fast with a brutal chain of NPs. 
• The Black Grail: Launching successive NPs quickly can be very nice in more challenging AoE encounters, but the sheer damage provided by The Black Grail will enable Masters to finish off the encounter faster especially if Masters can quickly charge her NP with other Servants.