Reposting (changed the formatting a bit) from the snapback/incoming character thread:
A couple setups I’ve found for fighting Phoenix specifically - you have to choose what you think is appropriate for the situation:
As she’s incoming - Sphere Flame, X-factor, Throw. Two strategies in one, but high risk since you lose your X-factor. If Phoenix presses a button for an air dash as she comes in, she gets killed by the Sphere Flame, but if she blocks, Sphere Flame hits her on the way up and scares her into not pressing buttons while you go for a throw before the Plasma comes back down. This method works pretty well as a way to go offensive against Dark Phoenix if you failed to kill stop her from coming out, but only if you can get the chance to throw Sphere Flame. I generally save this for Phoenix players that transform into Dark Phoenix early and then tag her back out to build meter. That way this mix-up results in her death right away.
Dante/Doom Team specific: Sphere Flame before Phoenix comes in so Sphere Flame misses on the way up, DHC into Devil Trigger, mix-up with a cross-under or Air Trick. DT works best since Dante has a teleport, but other characters with Buff Hypers would probably be able to benefit from this tactic. With Dante, you can perform this tactic even if Phoenix (or even Dark Phoenix) is already on the battlefield from anywhere on screen because of his fast teleport.
Fight her like a boss after she’s transformed. Honestly, I feel like Doom can hold his ground better than almost anyone else in the cast against Dark Phoenix because of Photon Shot, Molecular Shield, Photon Array, Sphere Flame, and Doom Time. Basically, if you think you’re not going to be able to kill Phoenix in time, start saving up meter for this fight afterwards. If you have 5 meters, then you should be able to drain out almost all of her X-factor, even without the use of X-factor - and if she doesn’t block, there’s a good chance she’s going to teleport into a Photon Array - which is death if you haven’t used your X-factor yet. Even if you don’t kill Dark Phoenix during your projectile fight with her, you should be able to eat up most of her XF3 time to make it more of a fair fight.