Pray to the RNG gods that you get procs during lust/execute.
Sac Pact needs to be used prior to large incoming sources of damage while we are ideally at as close to max health as possible. Good culprits are fire soaking, phantasmal wounds, multiple radiance stacks, and chakrams.
Be more conscious of other players running fire through us for no reason. We'll naturally have high fire damage from soaking, but there's quite a bit more than we should have. I think we can push damage taken even further down.
Use Healthstone for this fight (with the glyph of course).
Dot uptime is very good here. We both have some uptime loss, but it occurs at exactly 3:20, which is where a stop dps call was made. Hopefully the lapse isn't long enough for dots to fall, but if it is maintain Agony (due to its ramp up) and forget the others.
As affliction we don't have the luxury of running the Healthstone glyph so Healthpots should be used instead. More efficient. Just remember that the HS is being used almost like a cd because it is a hot, whereas the pot heals instantly so we need to make sure we are low enough to make use of it.
Try to time Doomguard so that it is cast immediately preceding the ring and lust. Casting it during those buffs means we just lost a gcd. This will of course take time and will likely change week to week.
We can cast a very early Sac Pact and still have it up for the first Disarm phase when we really want it rolling. This first one won't do much, but it'll do something.
2 casts of lifetap. Just use the glyph for it. It'll prevent any instance of needing mana and using tap in a potentially dangerous spot, and it'll save us a couple gcds per fight. Even if tap is being used during movement when drain cannot be, we could still just do an early agony/corruption refresh (or cast bulwark) here. Not the most efficient, but better definitely more so than using tap.
For the first two adds spare haunts should be going to Tyrant to maximize uptime on the debuff. Boss damage is the priority here. The only time we should alter this is if we're getting ridiculous procs, or we have DS up and can rotate drain to refresh the debuff on both targets.
Anytime we have multiple targets as affliction Siphon Life is probably going to be a great glyph. MVP for sure on this one.
When the 3rd add is out it is the priority. Only refresh Agony on Tyrant due to the ramp mechanic. Do not sit there and drain Tyrant.
I'm unsure of the approach during lust for this fight. It's certainly more efficient to pop everything here (we get lusted pet, ring proc does full damage on both targets, great drain uptime due to minimal movement), but things seem to get really chaotic during p3. Probably a coincidence that the pull I saved things for p3 we killed it, but again, I can see an argument for both approaches. If dps seems fine, and the transition out of p2 is being done within a reasonable time, think about saving things for the p3 add.
Unsure of defensive cd approach for this fight. The lowered health mechanic butchers Sac Pact's effectiveness once it goes out, and that's the phase where we need it the most. Taking Soul Link for the 20% health boost gives us a safety net during the later phases in a way that Sac Pact cannot (due entirely to the health loss mechanic), and it augments Siphon Life directly and Soul Leech indirectly. However, because Touch of Harm does damage based on current health, and we should have generally higher health with Soul Link, we end up causing this debuff to due more damage than it typically would. Of course the counterargument here is that getting targeted by ToH is random, the other mechanics are not.
Generally pleased with Soul Link on this fight, but that doesn't mean it's actually the best choice.
Try to push damage taken down. A lot of oppression damage that I think we can manipulate a bit better even with the occasional melee running around last second causing extra movement.