Drones

Drones, often called Minions, are weapons used by some tanks. Most look like smaller versions of Red Triangles (Or blue when controlled by a member of a blue team). An exception are the Necromancer’s drones, which are squares.

Technical
All drones (with the exceptions of Guardians, Hybrid Drones, and Overtrapper Drones) can be controlled via left click or by using auto-fire, causing them follow your cursor. Right clicking or pressing shift will cause them to move away from the cursor. If the drones are clumped together under the mouse pointer when doing this, they will spread out, but if the mouse pointer is to the right of the drones, they will go to the left and vice-versa. They will automatically seek the nearest player or Polygon if not controlled. A Hybrid's drones cannot be controlled but will still seek nearby enemies, as well as the Overtrapper’s drones. A Mothership can have up to 16 controllable Drones, and 16 uncontrollable Guardians that will automatically protect the Mothership from enemy tanks.

Users
Tanks that uses controlable drones are: Tank that uses uncontrolable drones are: Tanks that uses both controlable and uncontrolable drones are:
 * Overseer: 8 per tank
 * Overlord : 8 per tank
 * Manager: 8 per tank
 * Necromancer: 20 + 2 * Reload/Drone Count per tank
 * Hybrid: 2 per tank
 * Overtrapper : 2 per tank
 * Mothership: 16 controlable drones and 16 uncontrolable drones

Trivia

 * After the June 15th changelog, when you upgrade to drone using tanks, Bullet Penetration, Bullet Speed and Bullet Damage will, respectively, become Drone Health, Drone Speed and Drone Damage. For Necromancers, Reload will also change to Drone Count.
 * A Necromancer’s maximum number of drones increases by two for every skill point spent on Reload/Drone Count. Combined with a basic maximum of 20 drones, a Necromancer player can have up to 34 drones under his/her control depending on the number of skill points spent on Drone Count.
 * There is a special kind of smaller, AI-controlled drone exclusive to team bases and the Mothership. While no official name has been given, the wiki has dubbed this sub-class of drone, Guardian.
 * Unlike other classes that use them, Necromancer tanks do not spawn drones on their own. Instead, the player must run into Yellow Squares to convert them into Drones.
 * In older versions of the game, a Necromancer drone would occasionally, albeit very rarely, spawn from the side of the tank. This could not be used to reach the maximum drone capacity however, as it would take many hours or perhaps even days to reach even 20. Considering that Servers don’t stay open that long, it would be an impossible task to accomplish via this method. Its ineffectualness was likely the reason why this feature was later removed.
 * The size of Drones increases based on the tank’s level.
 * Occasionally, Drones or Guardians can be spotted surrounding and trying to attack another Drone.
 * This is a result of controlling your drones while your cursor is stationary. As all the drones pile into the same space where your cursor is, it gives the appearance of them cannibalizing each other. No damage is actually incurred by your drones when this happens however.
 * Many players of Diep.io prefer to name the triangle Drones "Doritos" rather than its official term. It is a slang in Diep.io and not an official term.
 * This is because its shape and color resembles Doritos, a brand of seasoned tortilla chip.
 * Another Slang term is "Sunchips" which is used to describe Necromancer's square drones.
 * After the July 18th changelog, a new class of Trapper tanks were added, Overtrapper spawns two uncontrollable Drones similar to the Hybrid.