Well he only does the a2 every 3 turns. So in 20 turns rhaz will only attempt the debuffs 7x. So he landed 100% of time.
Problem solved!
I dont mean 20 turns. sorry. i meant 20 times. I have rhazin archmage septimus coldheart and royal guard. If he lands both debuffs from the start ill kill the spider in 12 sexonds. If he doesnt, i dont get the kill. So thats 20 fresh starts.