How do you defeat Black-Winged Divine Storyline post-game? [Spoilers]

[Shinelite]

I have completed every challenge and have every achievement except for this one.

The challenge is to defeat the Black-Winged Divine. Not Satell. This is the version you fight before you know his name. He still has Divine Immunity. He's immune to damage and debuffs. But his health goes down over time naturally.

I have been experimenting.
- I have been able to wait him out to 9.3M / 10M health before he just suddenly wins.
- The only way to stop disease is to minimize the cooldown for Status Shield. I'm able to get mine down to 5.56 seconds. I still need Dispelling Salves for times when something still gets through.

- I could use the Stone Egg to prevent Airborne from triggering Status Shield, but other accessories seem better than the Stone Egg.
- Using +15 Vampiric Platemail & Shapeshift Mouse, 53x boost in Poison, 53x boost in Life, 3x boost in Earth gets my defense and dodge high enough that my healing can usually outstrip his defenses
- Using a Goblin Doctor familiar, in the back row, so that he sometimes heals me too
- Spellcrafts all focused on reducing Status Shield's cooldown, and the cooldown for all the healing spells
- My main Synchro Board is:
Fire-Earth-Water
Earth-Water-Earth
Fire-Life-Fire

Possible solutions:
- There's a secret to this that I just haven't discovered
- I need to stop whatever instantly kills me around 9.3M health remaining
- or I need even more healing & defenses
- I could also try changing my Primaries to Holy and adjusting the Synchro board to boost Primary Protection. That gives the Bun familiar but I don't think that'll be any better than the goblin doctor.
- My class is Sage, which doesn't jive with my strategy. Maybe Breeder or Cultist?

[Barbiz]

**Spoilers**
So I went into Black-Winged Divine overpowered as I was getting ready for white wing.

Sage w/ Space & Mind
Sychro Board 3xTime, 3x Space, 3x lightning
20 Spell Catalysts
all the buff spells perma-cast, all rituals perma cast
lv15 Cosmic Want, Robe of Mass Healing, Synergizer, Fool's Cap
Lv70 all elements except lv80 mind/space (lv74 water/death/holy for crafting)
Boosts 30 mind, 27 life, 58 holy
BigBang SpellCraft Holy Jewel & Electric Jewel

This lets your Big-Bang deal 22M+ damage every 7.29 seconds, it one shot Black-Wing, and with the correct pouch items White-Wing only took me 2 attempts.

[Shinelite]

I figured it out on my own a little bit after posting. This whole time, I did not know you could create Divine Crystals. I thought you had to farm them, and that they couldn't be created. I just stumbled across them in the transmute menu now. That solved the problem I had.

I accidentally beat the Black-Winged Divine after noticing this. I was quite surprised to hop into the fight and see him at half health instead of 9.5M!