They had snuck into the council under the cover of Gideon's darkness while Dan teleported some of them in, other vampires with similar abilities helped the rest of them, and the already commenced battle began to reach its peak.
Their enemy was clear to them - the council and the dark witches. They were not taking any sides here. The Dark witches wanted the witches' apocalypse while the council wanted Lia dead - unknowingly benefiting the dark witches with their plan.
That was the secret Vashti discovered, the Burning Eaglet had played them. They unknowingly helped the enemies with their agenda.
It was a tough battle, Daniel's pack with a whole lot of others had joined forces with the vampires on this one. The council had treated them as a minority race, choosing to concentrate power amongst their fellow member witches, leaving them with nothing. It wasn't surprising it resulted in this rebellion.
