Black Knight

BK’s fun at +10! The result of my grail-work. Standard Alondite and Black Luna, since they’re both great already, Swap because he’s generally used on my armor emblem team. The build mostly explains itself- at +10, BK’s got enough speed to hold his own against a lot of matchups, but Bold Fighter works to ensure he consistently doubles at the added perk of special cooldown acceleration. Ward Armor since, as said before, I use him on my armor team, finishing off with Steady Posture in the seal slot to grant him an extra boost in enemy phase.

Weapon: Alondite

Assist: Swap / Pivot

Special: Black Luna

Passive A: Steady Breath

Passive B: Bold Fighter 3 / Special Spiral 3 / Special Fighter 3

Passive C: Threat. Atk/Def 3

Sacred Seal: Brazen Atk/Spd 3 / Quick Reposte 3

This set aims to make Black Knight a speedy physical tank with high damage potential and good speed to nullify most follow up attacks against him and maximize his own follow ups.

Alondite and Black Luna are self explanatory, distant counter capabilities with arguably the best special in the game.
Now onto the actual explanation.

The combination of Steady Breath and Bold Fighter 3 makes him able to charge his special by +2 through both phases making Black Luna practically a guarantee through all match ups.
Steady Breath has the added benefit of Def +4 making him have a Def of 44 under ideal situations.

The combination of Threat. Atk/Def 3 and Brazen Atk/Spd 3 is there to raise all his key stats to Atk 62, Def 44, Spd 41 under ideal situations.
Sadly Threat. Atk/Def 3 will weaken Black Luna due to the -5 Def but, with the +12 Atk from itself and Brazen Atk/Spd 3 more than makes up for it.
The Spd +7 puts his Spd at a sweet spot in most cases, it's fast enough to keep Spd built units from following up on him and allows him to follow up on most average units.
In conjunction with Bold Fighter 3, during player phase he would be able to follow up everything while not being followed up by most.
During the enemy phase he would still be able to keep most Spd built units from following up on him but lose the ability to follow up on them but against average units he would be able to keep his follow up due to the sweet spot his Spd stat would be at.

Now for budget/alternative skills, both Specials (B Skill) will still give him a quicker way of using Black Luna but at the cost of a guaranteed follow up attack while initiating. Spiral would help proc Black Luna almost every battle while Fighter allows him to have +1 charge per attack while giving a -1 charge adding to his survivability.
Quick Reposte 3 as his seal would work really well with Bold Fighter 3 as it would guarantee follow ups on both phases but at the cost of having to be ≥80% Hp and once you dip below that it becomes useless while Brazen Atk/Spd 3's ≤80% Hp threshold is just as easy to get to while having a longer window of viability.

If you're going for the budget/alternate skills I'd highly recommend going with these combinations of:

Quick Reposte 3 and Special Fighter 3.
Losing Brazen Atk/Spd 3 will keep his Spd at 35 meaning anything with 40 Spd or more will be able to double him and Special Fighter 3 would help mitigate any specials from procing on him.

Brazen Atk/Spd 3 and Special Spiral 3 (This is the alternate setup I'd recommend)
Unlike the other alternate setup this would keep his ability to not be followed up easily and after the first battle almost guarantee Black Luna every match.
During enemy phase Black Luna is guaranteed, during player phase it is only guaranteed against average Spd units as with a Spd of 41 Black Knight should be able to follow up.

If he's the only armor on your team, use Panic Ploy instead of Fortify Armor. Instead of Wrath, you can also run Special Fighter. His seal can be Quickened Pulse, If you want his special even faster.

I don't use that build atm, because no grails, but it'll be the build I'm gonna use. I don't want to use Bold Fighter, because, first, I have no fodder, second, I don't like the mixed phase thing. I like using Wrath in general, because 10 true damage, if I don't use Desperation or Vantage on the unit. The build costs 2080 SP, if used with Panic Ploy, and 2010 SP, if used with Fortify Armor.

Side Note: My Team is standard Altina, Default Nino (Fury+Desperation), Standard Peony and V!Faye (with Armor March)

Black Knight, wielder of Alondite and Black Luna. This build is focused around increasing defense. It probably would've made more sense to give him Vengeful Fighter, rather than Bold Fighter. But I only had Bold Fighter at my disposal.

Summoned on April 4, 2019
(Currently LV. 40 with 2 Dragon Flowers and Earth Blessing)

A pretty straightforward build, that basically utiize BK's speed stats without using bold/vengeful fighter. On enemy phase, it is insta proc Black Luna with extra +5 atk from Atk/spd bond. so unless you one-shoted BK, you are gonna have a bad time. You can also use fierce stance on seal if you just gonna focusing on pure damage.

I recommend having another armor unit along side with BK, to provided him with Hone armor for extra atk and spd, also armor march from BK help with mobility issue.

Even thougth he is a Gen 1 unit, BK still a monster that will destroy tons of units regardless of triangle advantage.