Only thing I can think of is:
Tanee Card?
Gospel Buff.
Stat Food.
SP Song Buff.
But if he really had NO buffs at all, then... I guess either Hacks or Tanee.
Maybe you accidentally swapped your armor for a second?
I've tried Stat foods, and they help but not enough to give 30k more damage. The highest damage I've seen on full Neutral reductions is 15k ish or so. Now that you mention it, perhaps Tanee? If that's the case, though, he would've died after I spiraled him 3 times for full damage and he didn't pot.
Would Tanee really give 30k more damage to asura?
double sp buff from gospel with the sp song and attack buff
Dispelled when you go into PVP. Unless they changed it?
Edit: Oh, and no I didn't swap. I know Walshy only Asuras so I just stick GR and Devi for him and I wasn't frozen.