FF XIV Stormblood - Stone, Sky, Sea O4S - Dark Knight (3383 DPS)

Yes, I know. There's waaaaaaaaaaaaay too much Critical Hit in my secondary stats. Determination is the way to go and you should try to get as much as you can.
Anyways, here is a simple demostration of my rotation as a Dark Knight.
--TIPS--
1.- There's always a priority for your Dark Arts on skills and offensive cooldowns, and it goes like this: Carve and Spit - Bloodspiller - Soul Eater - Syphon Strike. The fact that Carve and Spit is still your top priority is because you want to use it as soon as it is available so that it starts cooling down. Bloodspiller, however, even though it has more potency, it doesn't matter if you dely it to prioritize Carve and Spit since your gauge can still be charged up.
2.- 1 Syphon strike without grit: 1200 MP. 2 Syphon strikes without grit = 2400 MP. Dark Arts cost = 2400 MP. So basically you need to do 2 Soul Eater combos in order to get 2400 MP when blood weapon is not on.
3.- If Carve and Spit has less than 15 seconds on cooldown, and you have less than 2400 MP, DO NOT USE DARK ARTS aftewards in your GCD rotation. Recover your MP, keep an eye for when the cooldown is over, and use your Dark Arts with Carve and Spit.
4-Blood Weapon is VERY IMPORTANT, so is Delirium. Blood weapon must be used as soon as it is available, and if your Delirium is up, use it on your Blood Weapon to extend its duration. It's a huge loss not to do this, since you're ditching away 23 seconds of 20% increase in Skill Speed, 720 MP recovery per hit, 2400 MP recovery from delirium, and the mitigation of your gauge.
4.- Salted Earth and Plunge must be used ASAP, but Blood Weapon is still more important. The priority goes like this: Blood Weapon -
Salted Earth - Plunge.
5.- Now, the priority for all the offensive cooldowns together: Blood Weapon (Delirium) - Carve and Spit (With Dark Arts) - Salted Earth -
Plunge
6.- The total potency of your DPS combo without DA is: 150 + 250 + 300 = 700
The total potency with DA is: 150 + 390 + 440 = 980
The total potency with DA in Syphon is: 150 + 390 + 300 = 840
The total potency with DA in Soul Eater is: 150 + 250 + 440 = 840
This means that wether you use one DA in Syphon or Soul, the potency won't change at all. But bear in mind that your Direct Hit rate and Critical Hit rate can greatly vary the increasement of your damage if you're lucky enough, and hence why you should use DA on Soul Eater if you can only use one DA.