Eliphas sees some jet interceptors flying above the city. "I knew that they'll come back, but their aircraft will not save them from the inevitable defeat. Basilisks, prepare Rot Plague shells! Today, they'll all turn into rotting corpses..." Said Eliphas to Chaos Basilisks via vox-caster. Eliphas prepares his Power Fist and tells the Chaos Marines to charge against the Men of Iron.
Rip and tear through the ranks of Men of Iron.
If successful, stop Rethi-Eli from escaping
Decimator Tank: Shoot from Decimator Cannon one time at Armnotok, then drive away from him and help the main army destroying the Men of Iron.
Nurglite Sorcerer: Make Ithadham's body rot at insane rate.
Squad Gamma 1: Hold the line against US military.
Squad Epsilon 3: Use rocket launchers to fight the enemy's aircraft.
Plaguebearers: Stop Rethi-Eli from retrieving the body.
Squad Epsilon 4: Bombard US military with "Rot Plague"* shells.
Predator Tanks & Land Raiders: Prevent Diablo from hurting the infantry by overwhelming him with fire.
Chaos Marines (main army): Destroy the Men of Iron.
Havocs with Multi-Meltas: Melt the Men of Iron.
Chaos Sorcerers: Open a huge, invincible** Warp Portal.
Chaos Raptors: Throw melta-bombs at the fanboys of Milkdrinker.
Dark Apostle Anak's forces: Regroup and attack Concord.
* They cause sheer necrosis and heavy diarrhea via breath and skin contact.
** By "invincible" I mean "can't be destroyed/closed so easily". It's still can be destroyed/closed, just not with the average tricks.
Also, Eliphas uses Power Fist, so please change "Eliphas severs Rethi's left arm" to "Eliphas rip off Rethi's left arm". Was Plaguebearers' summoning a success?