Turn 3..ugh forgot to make notes at this point, but it was mostly cult marines and infantry companies chopping each other up
Remaining imperial terminator formation teleported in behind the right hand portal objective, and picked up 1 BM.
Concentrated firepower throughout the turn from land raiders, the Shadowsword and the Reaver brings the gate crashing down.

Khorne berzerkers assaulted the dismounted infantry company, winning the assault with 11 stands of guardsman dead after resolution. Unfortunately they are themselves reduced to 1 stand and a couple of rhinos.

The defilers patrolling the right hand walls sustain on the imperial SC tactical formation, taking out all 3 rhinos and leaving 3 tactical stands to perish in the wreckage.
The remaining gorgon infantry company attacks the right hand portal, assaulting the plague marines holding it. Another bloody fight, after a couple of rounds and some very effective supporting fire the plague marines are wiped out, but not before they kill 14 stands of guardsmen, breaking the infantry company.

The blood slaughters assault the drop marines on the left portal, wiping out the tactical formation before being shot to pieces by sustaining devastators.

CS terminators danced about a bit with the leman russ platoon, who lost 1 tank while the daemon price refused to die. Blight drones pew pew the whirlwinds some more, take a second turn of fire from the speeders and break.
End of turn 3, Objectives 0:0, (marines have half of take and hold
Don’t have a casualties photo, but 20+ stands of guardsmen were killed, all bar 1 stand of cult marines were destroyed. 10 or so stands of marines perished as did a few blight drones and all of the slaughterers.
Most things rallied, apart from the central gorgon inf coy, which retreats back along the road.
Turn 4Chaos are now very low on activations.
The wall defilers on the right having broken the SM SC last turn and contributed to the breaking of a DKoK inf coy, the imperial firepower concentrates on their wall section, bringing it down with ease. With a similar ease the defiler pass all of their invulnerable saves, and glare menacingly at their attackers.

The defilers rush forwards, pass two sets of difficult terrain tests and rip apart most of the remains of the infantry company holding the portal.
The single stand of berzerkers+rhinos chance an assault on the 3 tactical stands containing the imperial SC, but after killing one stand are themselves wiped out in a second round of combat.
Somewhere along the lines the shadowsword sword managed to kill itself on a DTT while trying to get into the fortress. The vindicators fared somewhat better here, clearing the rubble, only to be attacked, broken and forced back across the rubble by the remnants of the chaos SC ret which had been skulking at the base of one of the towers.
Having managed to contest the right hand portal with defilers, the remnants of the blight drones and a lone CSM character stand move to attempt contest the left side. The character stand is killed by land speeders.
End of turn 4, Objectives 0:0
Turn 5Chaos are now
very very low on troops
The remains of the CSM SC ret move up into the tower to the right of the destroyed gate, just in range to contest it as an objective. The vindicators move in again and the forces of the imperium sustain on the tower with many of the remaining formations, desperately trying to take out the blitz contesters, but to no avail.
Imperial fire on the left flank breaks the blight drones contesting the portal, the drones flee into the fortress.
On the right flank the hero-defilers scuttle about, inflicting few more casualties and losing one of their own to the imperial terminators.
End of turn 5, end of game, Objectives 0:0 Imperials have the left portal for half of take and hold, the blitz and right portal are contested. Neither side has achieved BTS. We worked points out, only 90pts difference in kills, in favour of the Chaos forces. However, chaos are now down to 7 stands (3 defilers, 3 traitor stands, 1 blight drone) and had well and truly lost control of the fortress.