Slow Skullcrusher and Tower
248 - Tower
186 - Doompriest or alternate cleanser
175-178 - DPS
174 - Skullcrusher
173 - Grizzled Jarl or alternate 3 turn debuff blocker
Note: This differs slightly from u/abscity's original guide. Here, both DPS are in the 175-178 range; this gets into fully unkillable faster, and avoids having TM ties between Tower and Doompriest that can wreak havoc.
The 186 will always go first after AOE2 to cleanse debuffs and before Skullcrusher to cleanse the Stun. Doompriest can cleanse both and as such is an ideal fit to make this affinity friendly.
If you're using Grizzled Jarl instead of Doompriest, then you want to replace the 186 Doompriest with a 186 DPS and one of the other DPS champs with a 173 Grizzled Jarl.
Roshcard's A3 needs to be fully booked out to a 4-turn cooldown. (2 books)
For UNM:Start with Rosh's A3, and then at the end of Round 2 use Skullcrusher's A2, then you can hit auto.
For NM: Start with Rosh's A3, and similarly at the end of Round 2 use Skullcrusher's A2. The key difference is that at the start of Round 3, you want to use Rosh's A1 then you can hit auto.
To run this against affinities and for thorough insight on this composition, read the incredibly detailed guide by Abscity!