I figured out how to replicate the video.
He's using ab buffs, Wanderer SP, Paladin Gospel with double HP, double SP and probable improve atk.
after he get the desired buffs from gospel he does gx claw, and ab lex.
I was really lost because I did'nt new about this ability gospel. So i tried ab bufs, paladin gospel and could get 18m sp and hit 24m asura damage.
Gospel is the key to improve that much dmg. with a messy work from 3 acc i got 80m dmg. very close to 101m.
I know is possible to hit 300k+ dmg.
All this is just for fun, asura is not a good dps and any Gx can hit harder.