Sentries are a special kind of device that mimic a gim. They have rapidly evolved over time.
Evolution
Origin:
The sentries originated from chemical supreme, a highly dangerous chemical that caused the growth of the original plant sentries, which had a wooden wand as a weapon. They had two appearances, pink and green.
The Robotic Age of Sentries:
Some sentries found that it was better to change their appearance to a more robotic look, and sentries then gained the ability to take on other weapons.
The Device Age of Sentries:
Sentries were being tamed, and now could join the side of a gim's team. New technologies were developed with devices to transport the sentry.
The Aggressive Age of sentries:
Sentries suddenly dropped compatibility with other devices and could not move, investing more of their time into combat. Sentries originally made friendly to all gim's and others broke free from their device systems.
Different sentry sub-species
Green plant species:
The green plant species are a species of sentry that have evolved to reproduce at high rates. Because of this the green plant species are generally much weaker then their pink counter parts. Very few of this species decided to go the robotic route. Their weapon of choice is a wooden wand.
Pink plant species:
The Pink plant species are a species of sentry that have evolved to be strong. Because of this they do not reproduce as quickly as their green counter parts. Many of this species decided to go the robotic route. Like the green plants, they mainly use wooden wands.
Robot species:
With the discovery of a unknown vessel the sentries discovered that they could change their own appearance. This led to the creation of the robot sentries. Robot sentries have adapted to focus more on shields rather then health. These sentries have a much more broad capability with weapons, however they still mainly specialize with the zapper. They also have a very broad range of reproduction and health/shield + damage.