Es/Advisor
Los Advisors Combine (consejeros) are a race in the Combine to which the posthumans are enthralled. They seem to direct operations on behalf of the Combine (if they are not in direct control of it themselves).
The combine Advisors follow a unique life cycle. They start out helpless, requiring the aid of an incubation pod to survive. Eventually, as they age, they gain enough strength to leave incubation. They soon realize the power they have when they search for food, being half-starved being in the incubation pods for quite some time. Searching for food, they generally discover their power while chasing their target. Once the target gets to a certain distance, the advisor, feeling hopeless, will discover that it can pull the target to itself. They also discover their mind probe ability, which is the concussion effect you see in Half-Life 2: Episode One. They discover they can not only use the mind probe to read minds, but also discover they can use it to stun their prey. Once the advisor reaches a height in strength, these abilities become much stronger. Eventually they arrive at a point which they are able to... persuade... anyone to listen to them.
Los advisors en Half-Life 2: Episode Two
En Half-Life 2: Episode Two los advisors aparecen "en la carne".
Habilidades
The Advisors have the ability to manipulate objects in telekinetic way. They have been observed to levitate (they have no obvious locomotive limbs), crush metal barrels and human corpses, lift and throw objects and even tear open buildings.
They also seem to have an, at least, basic grasp of telepathy and are able to induce mental pain in humans. The mental pain seems to be a side effect of the mind probe.
Equipo
Los Consejeros Combine están recubiertos por una especie de traje. Al parecer, se han vuelto tan dependientes de la tecnología que no podrían sobrevivir sin ella. Montado en los trajes son un par de brazos para permitir que los asesores tengan algún grado de control de la motricidad fina. Esto implica que sus habilidades telequinéticas están limitados en formas que requieren la manipulación directa. La maquinaria de los trajes, una vez se especuló para proporcionar funcionalidad de antigravedad. Esto puede no ser el caso, teniendo en cuenta habilidad telequinética del Consejero.
It is also possible that, like most other combine creatures, this "jump suit" is built into the being. Notice striders are naturally made of a sort of metal, as well as gunships and dropships. This would hint that most combine organic material is similar to metal. This would mean that the advisor is probably just another metal-like creature.
Proboscii
At least some Advisors have a prehensile proboscus. This has been seen to be used to penetrate human skulls with a stabbing motion. The method was deliberate (twice witnessed), and implies intent. It has been suggested that the most likely explanation is they use this to read memories from humans. However, since in at least one case they do this to someone who seems to have been dead for some time (the corpse of the rebel that Alyx finds draped over the Advisor's life support control panel in the barn), such an interpretation lacks credibility.
According to the commentary in episode two, this is actually how they eat.