i just wiped it like 30 mins ago after 40 odd mil regearing champs, training champs, anax was mint for damage up til 21 - stage 21 he was too squishy but i was lucky i pulled saito last week and this was first run with the team rebuilt.
ive been stuck on this floor with 1 star for ages, lydia is now mine yew
looking at your roster vogoth, zelotah, maus mage, nethril & seeker but you have some decent additional champs in dark elhain and grinner who would be handy aswell
there are some great knowledgable people on here who will be on to help you out - my suggestion above me guessing as i dont have nethril or seeker but i know seeker would be mint and nethril a2 will help control the valks wave 2
i had my team built with lowest hp saito 52000 hp, highest was zelotah to help his hp shields on all champs 75 500HP, i had the others around low 60 000hp. Speed seemed to be the key for the boss my team had 4 champs running 215 - 225 speed and vogoth 173.
good luck its a friggin hard faction til you get the right mix of gear etc, my zelotah was in a set that gave HP shield at start of each round
if your stuck for damage anax hits hard but you have that covered by sounds of it
if your losing champ give grinner a try make him tanky as and get him to pick up champ with his revive - gorgorab better as aoe revive but grinner is used in plenty of other teams ive seen that have wiped undead hordes