Confirmed that the Deff Dreds can leave the center area due to a patch. (Thank you Nonfaith)
The wave is comprised of Orks centralized around one unique set of enemies. Everyone
remember the ork walker from the old Space Marine trailers?
They are called Deff Dreds and are essentially Ork Dreadnoughts. They have several attacks, two melee, one ranged and a clumsy charge. The melee consists of a quick slice attack which will drop your armor and roughly 1/3 of your health but is survivable. The other is an overhead slam that either kills you outright or drops all your armor and roughly half your health. The ranged attack is a heavy duty machine gun barrage that is literally announced by a very loud and kinda annoying screech as the gun starts up. Hiding behind anything is safe but it can kill you easily if caught in the open. The charge isn't worth mentioning because its easy to dodge and limited to the center area.
The wave starts off with one Deff Dred in the center of the arena . Once you do some damage to it, a second Deff Dred, Ork berserkers and rokkit launchas spawn. You can take as long as you want fighting the orks as long as you do not kill at least 1 of the Dreds.
Second part of the wave happens after 1 Dred is dead and you start hitting the second. 2 Dreds, alot of Ard Boys (Shields), squigs and more rokkits spawn. Same process as above, take all the time as you want killing the orks as long as the Dreds are left alone. (Any noticeable damage will signal the next wave)
Third part is a challenge. After you kill 2 of the 3 current Dreds on the field, 3 more Dreds spawn for a total of 4 on the map. Along with this are a mix of Nobs, both Shoota and the melee ones that carry a mace and a large amount of squigs. Again same process as above. After you kill 1 or 2 of the 4 Dreds. Hell breaks lose.
Fourth part of the wave consists of another 1 or 2 Dreds spawning bringing the total up to four again. Accompanying them is 5-6 Uba Nobs (the big axe wielding ones from your nightmares) and anywhere from 6-8 of the Rokkit Nobs.
NEW -
There is actually a fifth part that consists of more large Nobs and squigs. Same as above.
Classes and perks for our winning team:
Assault - Deamon Maul, Bolt Pistol, Killing Blow, Impenetrable
Assault - Power Sword/Chainsword, Bolt Pistol, Zeal, Impenetrable
Tactical - Bolter, Plasma Gun, Kraken Rounds, Weapon Versatility
Devastator (Essential) - Lascannon, Lascannon Capacitors, Feel no Pain
The Devastator is your MVP, he is your best weapon against the Nobs because his weapon can pierce through the crowd that will follow him.
Good Luck and may the Dark Gods protect you.