i'd for sure run warlord, rotos, arbiter and probably dhukk. warlord for cooldown and healing (plus a really useful aura), arbiter as revival, rotos as a dps. dhukk is mostly there for his aoe def down so you could switch him out for someone else with that ability, but i do like the cc on his a3. the fifth will depend on how well the team performs. ideally you'd want another dps because relying solely on rotos will mean some long fights, but you may need to put in some cc or support. someone like ninja or astralon who provides cc and damage would likely be who i tried first.

You mind sharing your builds for Warlord, Ninja, Rotos and hmmm.... Bystophus and Scyl?

For my Dec Def, I would be using Bystophus over Dhukk due to his Block Active Skills. That's fairly useful to stagger with Warlord to lock out the waves entirely as you DPS them out. Or potentially Uugo even, who comes with a nice cleanse and heal too.

Honestly you've got the champs to make several team combinations that could be successful in Hard DT. I'd like to see a couple builds though to see where we're at. :)

I'd want to be building around Ursala, Ninja, Warlord. With that we'll have a good amount of sustain, CC in Ninja and hopefully some DPS there with Ninja, as well. Demytha could make some sense too for buff extension/heals/block damage.

My first hard DT clear used Brogni/Lydia/Ursala/Ninja/Demy as the core. After figuring out your core it starts to become figuring out what answers you have to the questions as you go through stages.

Ursala is a good pick for sure.

Her speed aura in DT is great, and she brings a lot of great team support and debuffs we want to see. Inc Atk with Dec Atk AoE. Her revive is second to none.

Could easily see a Ursala/Warlord/Ninja/Uugo and now that I'm looking at the roster for longer, perhaps Drexthar. 

Control is king vs. DTH waves. You have good champs for that, Warlord (cooldown), Scyl (stun), Ninja (freeze), Bystophus (block active), Rhazin (tm reduce), Cleo + Ruel (block active + tons of damage, I love that duo), Giscard (provoke). Just use some of these champs, according to matching affinities of the opponents.

Stage 4 is quite difficult because of all the Warchiefs among the opponents. Your really hard hitting champs may kill themselves due to the reflected damage. So this is not the right stage for squishy hitters. I just finished it with Deacon, Scyl, Ruel, Cleopterix and Giscard for showcase. It worked, but was not the best choice for this particular stage, for the strange reason that Cleopterix and Ruel did to much damage. Scyl had to revive them after each AoE attack. Warlord shouldn't have that problem, he doesn't hit that hard and with 22k base hp he has better survivability.

P.S. Warlord shows Warchief who really rules in war. 💪

Thank you all, Finally got past floor 4!  that was painful, I've almost always focused on ACC/SPD/DMG.  Rarely did I need a lot of control.  But using Ursala, Warlord, Ninja, Scyl, and Demytha got me past 4 and moving on.  Thanks again.  I will share my builds as requested later.  I was going to use Bystophus, but Demytha's Block Damage is just too enticing and sexy 😂😂😂

Also, editing to my roster...Just pulled Lyssandra this morning!!!!!  WOOT WOOT!!!!

Congrats!

I should mention that Hard Doom Tower defense numbers are absolutely ridiculous. You absolutely will need some AoE Dec Defense in your team as you move up. Eventually you won't be able to outdamage some of the shields or passive healing in waves. 0_0

Okay, so now I'm stuck on Bommal...who's up for the challenge of helping me get this guy?

doompriest, aniri, vogoth, vrask, someone with an hp aura. i like using geomancer to speed up the match, but he tends to be a bit fragile and boosts the opponents offense, so you might be better off with deliana.

No one with a freeze for the bombs?

i wouldn't bother. you don't have any good candidates for that role (except ninja and good luck keeping him alive), but even if you did i've found that you're better off with another healer rather than a dedicated freeze champion.