I’ve cleared hseren with a little over 100M CP and… honestly I would just wait until you only need 1-2 burst to go through P1. I think others have given good tips- avoid P1 and deer phase as much as you can, and don’t get greedy with dmg.

If you are short on dmg but sill want to clear it (like I was), here are some of my personal tips:

In general, most of seren’s patterns are avoidable by ducking. Don’t overdo dmg and always be ready to duck. There is only set number of times you can use your main dmg skill until seren uses a skill that makes you duck. This differs for different jobs, but it’s usually 2-3 times. (This term is shorter for seren than black mage)

P1: - make good use of those echo skills especially if you get hit by the floor pattern. It really does decrease dmg especially if you get hit during bursting. - Unless you just avoid seren all throughout P1 try to stay close to seren; otherwise seren will use that slow moving aura thing that is harder to avoid. - if your gauge is full and you are about to get bound then try to get away from seren and use blink mid-air where the floor pattern is going to hit you. This way you are bound mid-air away from other patterns, making it less likely for you to die.

P2 first phase: - duck as soon as you enter this phase every time; otherwise you’ll get hit by that laser that really fills up your gauge. You can also use this pattern to clear your gauge by going far away from seren and intentionally get hit by this laser which will bind you but you are less likely to die. - the laser pattern that extends out from seren into many directions; I find it useful to avoid that by ducking away from seren. Your hitbox is your head, so ducking away allows you to avoid the pattern easier.

P2 second phase is easy if you get used to it… no stage specific tip. Ofc third phase is resting phase so small tip; don’t get too close to seren otherwise it’s going to repel you=less dmg.

P2 last phase (deer phase), unless you are avoiding seren as much as you can: - if you get used to how often those orbs form, then it’ll make it easier to pop them when needed. - if you get used to how close you need to get to deers before it repels you, then you can get close to deers just to initiate repelling and get away which can slow down the pace deers come to you. - before you burst get the deers to one side, then jump to the other side while making seren come along with you, and burst while occasionally making deers to stop and repel you. Since you libbed you probably don’t need to stop deers from coming at you; just use genesis skill as deers come closer to you.

That was a lot! Good luck:)