The following section contains information from StarCraft: Insurrection.
With the platforms secured, Syndrea believed it was time to attack the planet from orbit, an action which would destroy the terran colonists. Andraxxus and his friend, Demioch, opposed this action, and before Andraxxus left, he told Syndrea to preserve the terrans' lives if possible.
Instead, Syndrea proposed sending her three advisors – Demioch, his daughter Edullon and the archon Aedus/Xerxes to attack different parts of the planet's surface. Demioch was sent against Carvalho, site of the primary Hive cluster.
Edullon believed it was a suicide mission, since the area was heavily infested and Demioch wasn't being backed up by a fleet. She believed Syndrea was doing so because of Demioch's influence with Andraxxus. However, Demioch insisted on following orders.
Edullon was successful in her mission, but Demioch had not returned. Nonetheless, Syndrea ordered her forces to return to the space platform. Edullon disobeyed the orders, preferring to seek out Demioch instead.
Syndrea was left with only Aedus/Xerxes as a loyal ally. She ordered him to take his forces and set up a permanent stronghold near terran and Incubus Brood forces. During the mission, Aedus/Xerxes led an attack on the terrans. Aedus/Xerxes was next ordered to attack the Incubus Brood's primary harvesting operations in the Valley of the Shadow. This left the Incubus Brood starving for resourcing, prompting it to attack Aedus/Xerxes' base, as well as untainted terran towns. When Edullon contacted Syndrea to alert her to the latter, Syndrea ordered Aedus/Xerxes to destroy Edullon.
Edullon and Demioch, along with terran allies, fell under attack from Syndrea's vanguard. Aedus/Xerxes personally led the assault. The alliance defeated Aedus/Xerxes, who was killed in a duel with Edullon.
In the aftermath of her assault, Edullon and the New Dresdin Outlaws assaulted Syndrea's base and captured her. However, the Zerg Swarm assaulted their position and captured her. Syndrea demanded that the Swarm kill her quickly, but Nargil, cerebrate of the Fenris Brood, told her the Overmind intended a different fate for her. The remains of Syndrea's loyalists attempted to regroup with Andraxxus's fleet, but were cut down by the Zerg Swarm.