how much is discord damage? cant you eat it with trusts?
No idea but probably. I used to solo it without trusts because I did 150 of them to afterglow my Koga with scoria. (Trusts didn't exist at that time) Probably easier now with trusts. I did it PLD/DNC with Aegis 95.
Afterwards, I found that it's a lot easier with just one other single person with a MDT set. The avatars distribute randomly between the party. So if you have one other person more than 30' away from the PLD, the astral flow will distribute half on the PLD and half on the other player. As long as all the avatars don't overlap, it shouldn't kill you. It actually wouldn't even kill a mage with -50% MDT (gear+shell) with stoneskin.
Alternatively, you just sacrifice that other player every 25%. That also makes astral flow much weaker.
I don't know if BLU can kill it (I don't know how much magic defense bonus they can get or whether they can kill it before astral flow becomes an issue). But other than PLD, I do know that DRK's can do it because they can super drain a random slime in the area to get 8000-9000 HP before they kill PW and MDT the astral flow. SAM can also do well because Yaegesumi will absorb all Astral Flows. I prefer PLD still out of the mix. (since the spells still do hurt and Aegis does help with that)