The Battlesphere is the final air unit in the Volition building of the Wardens. It requires Air Superiority to be researched as well as an Eschaton building. 

Advantages: The Battlesphere does a decent amount of damage, while boasting a large amount of health. Furthermore, the population cost of a single unit is 2. This makes a swarm of 20 Battlespheres a force to be reckoned with, especially since a Battlesphere can engage both land and air units. 

Disadvantages: The light armor of the Battlesphere make it highly suceptible to enemy attacks. When not in groups, individual Battlespheres are extremely vulnerable. As the Battlesphere also requires copious amounts of research and buildings to be able to produce it, it is highly difficult to mobilize a large force quickly.