Drones are unmanned small ships, which are primarily controlled by an AI of a bigger ship.
The High Guard uses amongst others these types of drones:
Janus is similar to the Oracle drone in its mission specifications, but it is half the size and can carry only two of the modular sensor packages. The advantage of Janus is its relative speed and maneuverability, as well as the Low Observability technology it employs to disguise its position during combat operations. Because of its greater acceleration and speed, the relative mass that Janus can bring to bear in an attack can be far greater than the destructive power of Oracle. Janus is also more portable than its larger counterpart and easier to maintain, though it lacks a command and control capability for hunter-killer packs.
Oracle is a semi-sentient, autonomous spacecraft that can carry up to four different modular sensor packages, all of which are based on larger shipboard counterparts. It is used to provide medium-to-long range target sensing for offensive and defensive operations, and can lead "packs" of smart missiles on search and destroy missions. In attack mode, the main body of the drone drops its sensor packages for later retrieval and accelerates at relativistic speeds toward a target. The resultant collision can produce an explosion that ranges between a few kilotons and a gigaton of destructive power.
The Odin drone re-packages the Oracle system architecture in a physical structure capable of atmospheric flight. It is used during all phases of planetfall warfare, including surveillance, reconnaissance and C2 applications. The Odin can accept smart missile control hand-off from the originating platform or another drone, and is also capable of leading hunter-killer packs on search and destroy missions. Unlike its spaceborne counterpart, Odin is not an effective choice for attack operations because of its low speed. However, the Lancer Corps records several instances where hostile troops surrendered to an Odin even when no smart missiles or other attack assets were forthcoming. It is a testament to the effectiveness of the system and the Corps that their most reliable eye in the sky can produce victory without bloodshed.