Battle for Zeta-9

 

Spec Op's role
Phoenix Team, along with Autel 'Vadam's team, infiltrated the Covenant base through a hitherto unknown waste pipe used to drain unusable fuel from the power plants. The two teams were able to overload and destroy the reactor in the basement of a temple and kill about half of the Covenant forces, dramatically reducing casualties on the UNSC and Separatist side.

Separatist role
The Sangheili were the vanguard of the joint forces, as they had superior armor and weapons. They charged the disoriented Covenant forces in an attempt to cause further ruination, using their plasma weapons to dice the heavily armored Jiralhanae to bits.

ODST role
The ODSTs formed the second wave of the combined forces, bolstering the Sangheili and using their momentum. They focused on Kig-Yar and Unggoy, as their weapons were better suited for this task. Their basic shielding allowed them to fight better than regular marines, but they were still only fast enough for it to be useful behind minimal cover.

Covenant stand
The Covenant troops knew they were dead, and fought with the desperation of madmen. Fortunately, for the UNSC and Separatist forces, this made their forces disorganized and frantic.

Result
By the end of the day, all Covenant forces had been wiped out, and casualties on the UNSC and Separatist forces were judged to be minimal. It has also been noted that Ezekiel's decision to send Phoenix Team to Zeta-9 probably allowed the undermanned Separatist and UNSC forces to win.