Get fucked Balder. Dual Scarborough Fair No Accessories. It’s all you need. I tried going for some long combos but PKP into walls seems to be the safest and most reliable for racking up damage and building magic.
I was having pretty good luck hitting him with both PPKKK finishers before but it wasn't working out here. You can hit him out of some of his attack animations but besides that hitting him is pretty much just random luck outside of Witch Time. Sometimes you can kind of trap him into hits with held shots or interrupt his attacks, guns make it a lot easier to be aggressive here.
Try to start up the PPPKKK combo and dodge/panther offset the third punch. As soon as you get Witch Time enter Umbran Climax and you can use the shots on the sweep kicks to take huge chunks of health. He doesn’t seem to be able to dodge or block the Umbran Climax shots so it’s pretty safe to fully hold the kicks. Even though it fires a lot of shots the kick on PKP is much weaker in Umbran Climax. Later attacks in combos deal more damage with their shots.
Watch out for attacks continuing after launching him in Witch Time.. These will definitely catch you off guard a few times, but once you get used to them and running back into his projectiles you can use these to immediately get Witch Time again after it ends!
If you know how to do it you can really rack up a lot of extra damage with Panther Strikes. Bayonetta’s Wicked Weaves aren’t too powerful so every extra punch, kick, projectile, or whatever else you can hit him with help. It can be a LONG fight be your trying to be defensive. Revolving Feathers are pretty good against him but I wanted to beat him down purely with the Scarborough Fair. You can usually use the Magic Drain staff with the Rodin at the start of the first phase to help reach Umbran Climax faster.
Unlike the Masked Lumen fights you can’t start this one with any magic, Diomedes has his own magic bar. This actually makes it a bit difficult to use Bracelet of Time at the start unless you use a lollypop.
This fight is incredibly brutal and fast. But I really like that it's basically one long fight except for one short breather and auto-save point, I find it's much easier to get into a rhythm here than the stupid Masked Lumen I fight. Every phase in that fight has minimal health and the later phases are just really distracting, I hate constantly changing camera angles and mechanics in fights.. Masked Lumen II is pretty fun and epic but I still hate his instant sliding counterattack which thankfully Balder doesn't have.
I have a newfound love for the Scarborough Fair. The Umbran Climax really just destroys everything and they feel so reliable and responsive compared to a lot of other weapons. We'll definitely be seeing some All 4 One on Jeanne.