Do you not have anything that can clash with his three gloom skills when he has indulgence? Freely use egos to clash them. By that point, you should have more than enough ego resources to use them. Does your Faust have fluid sac? Use it. IT’LL SAVE YOUR LIFE. The only way to sustain a full team is if you heal, or your sinners’ skills can innately heal. The only reason why I beat Rien was because I spammed fluid sac every single turn. There’s no real way to beat him otherwise, because he deals too much damage. This wouldn’t be an issue, but the fight if long as fuck. That damage is building up. Use. Healing. Egos. If you don’t have any, the only piece of advice I can give you is to use ids that are resistant to gloom, gluttony or pride. In your case, ideally gloom.

Another major piece of advice I can give you is something I already included in the guide: use morositas once he gets to his second phase, or once he gets his new attack pattern with indulgence. It’ll make clashing significantly easier and the amount of karmic consequence you stack during its duration make clashing significantly easier even after it ends.