There are generally two variations to this comp, one fast and one slow. Both are listed below.  The slow is recommended generally as it’s usable on Nightmare as well as Ultra-Nightmare, with some minor gear adjustments.

FAST:

This works on UNM ONLY

This comp allows adding TWO 4:3 champ into an Unkillable Team.
Unkillable from Turn 1.

257 – Helicath
241 – DPS moving at 4:3
240 – DPS moving at 4:3 (Debuff Blocker)
192 – DPS
191 – DPS (Debuff Blocker)

257 and 240 go twice after the Stun, with 257 going last.
Use Helicath’s A3 at the start of turn count 1.

SLOW:

With a gear adjustment this will work on both UNM and NM.

This comp allows adding TWO 4:3 champ into an Unkillable Team.
Unkillable from Turn 5.

240 – Helicath
221 – DPS moving at 4:3
220 – DPS moving at 4:3 (Debuff Blocker)
172-178/190-192 – DPS (speeds are for NM/UNM)
171 – DPS (Debuff Blocker)

240 and 220 go twice after the stun, 240 goes last.
Use Helicath’s A3 right from the start.

Affinity Adjustments

You’ll want to avoid the stun going to anyone who will drop the shield from Helicath.  Generally this will mean avoiding your 221 speed champion.

You will need a block debuff champion with a 3 or 4 turn cooldown on that skill.  With a 3 turn cooldown a 2 turn duration is required. With a 4 turn cooldown, you’ll need a 2 turn duration as well as a buff extender (in the 171 spot). In all cases, unless tanking the stun, you’ll want to avoid the stun hitting your 221 speed 4:3 Champion, Helicath and your slowest Champion.