Just some quick abbreviations so there is no confusion.
FB = fireblast
RoP = Rune of Power
Combust = Combustion + Balefire (you can just macro them together)
So essentially with the combust there is a setup and then the rotation, and the setup depends on some things, but generally opener is always the same setup.
You always precast fireball, and as you mention it can either crit or not, meaning that your setup begins with heating up or without, so we will cover both.
Setup is just everything you do up until you combust, and you always wanna go into combust with 1 hot streak, and at least 2 FB stacks.
Setup Without heating up:
Lucid > FB > RoP > FB > Meteor > Combust
Setup with heating up:
Lucid > RoP > FB > Meteor > Combust
Now these aren’t ironclad, where you use the FB is not majorly important, but i prefer them like this so you always maintain BM, but the difference is small, some prefer to do combust and then 2nd fireblast into pyro, and it’s more or less the same damage, just preference.
Now you’re in combustion, you did your setup and you’re ready to blast, what do you do? Combustion is not consistent as procs influence how you play it, and reacting and playing around those procs is a good way to tell a good fire mage from bad fire mage. For the sake of explaining this and give a good understanding i will break combustion into 4 stages (which is pretty crazy for a 10 sec CD lul), but keep in mind these are just stages i am making up names for, for explaining this, you won’t see it in guides or anything.
So the 4 stages are:
Burn 1
Recharge
Burn 2
Sustain
So let’s explain each of them 1 by one.
Burn 1:
This is the first phase. You just came into combustion. You will have 2-3 FB and a hot streak ready. Here you just wanna go
Pyro > FB > Pyro > FB > Pyro > FB > Pyro > FB
Now how long you can maintain this depends on lucid procs and if you got heating up on your fireball.
There isn’t really much to this phase, just keep dumping pyros, like there’s no tomorrow.
Recharge:
This one as you could probably guess is about the mechagon bracers. You could argue that this is not a phase, but i put it in to put a few comments on the bracer use.
You enter this phase when you start to get low on FB, and you wanna start considering when you wanna use bracers.
The most important part here is that you always keep in mind that you wanna bracer after FB > Pyro > FB, the is like the most important part.
Another important thing here to make note of is, when you use FB and you’re at 0 stacks, but the next stack is close to recharge, when should you wait and when should you just pop bracers?
This is always gonna be a judgement call, but imo it really depends on burn 1. If you got a long burn 1 (say you go in with 3 FB stacks and get a lucid proc, so around 6+ pyros) then i would never wait unless we’re talking like 0.2s left or less, cause otherwise you might overcap (meaning going out of combust with more than 1 FB stack) which means you missed a pyro.
If you however got a bad burn 1 (going in with 2 stacks and no procs, meaning you get 4 pyros) i would wait if it is less than 1 sec probably, might depend on other things.
As for if you get a 5 pyro burn 1, i would say less than 0.5s
Burn 2
This is just exactly like burn 1, except 1 thing. In this phase you want to use your interupt when you’re running low on FB. Counterspell can trigger lucid and it’s off GCD, so it’s good to use. It won’t always be impactful, but it’s a good habit.
Note: only do this if you’re sure you won’t need counterspell for the next 24 sec, and in M+, be very careful with this.
Sustain
This is when you start to run low on FB again, then you enter sustain phase. You won’t always have this phase, but it happens, but it is usually very short. This is when you start scorching. Now how you do the scorch weaving depends on distance to the target, and when you scorch depends on your stacks and how exactly it lines up with the recharge.
Most important thing here is to not overcap crits and don’t lose BM.
If you’re a good medium distance from the target, then i usually go for Pyro > Scorch FB > Pyro > Pyro > FB
That’s my go to more or less, but in other situations you might have to go
Pyro > Scorch > FB > Pyro
It all depends on the recharge of FB.
Other notable things about this phase is that when you get your FB back, and you essentially have 4 sec recharge time, don’t use that FB, cause you don’t wanna sit with 0 stacks, 3-4 sec recharge on FB and cast a scorch, cause then you lose BM. This is a rare case, but it doesn happen, use FB if you have more than 1.5 stacks, any less and it’s time to scorch.
To practice this phase if you want to, go on a target dummy and do a combustion without bracers.
After notes i am too lazy to go back and edit in:
The distance doesn’t really affect the sustain rotation, just keep in mind pyro will be really slow to land if you’re far away, so you can in some siutations cast pyro and then while in the air go FB and another pyro before it lands. Only in really long range and BL.
Another really important thing that is the reason you have the 2 sustain rotations is depending on your spellqueuewindow, haste and internet.
If you do Pyro > Scorch FB > Pyro > Pyro > FB And you have low spellqueuewindow + high haste + bad internet, then sometimes the game won’t register you casting pyro before scorch, and therefore you miss a crit, this is really annoying, but it happens sometimes during BL, and if you’re prone to this happening i recommend the Pyro > Scorch > Pyro > FB > Pyro > FB.
That should just about cover everything, might have missed something idk, hope this helps.