Well not all of them are entirely Robots, Updated build from a long while back, Trimmed down and with newer style of building.

Based in a futuristic setting for the story I used to have.

Red Platform Character is a Cyborg who utilizes hand to hand combat, Red Ethurgy covers Fire Force Lava & Dragons

Blue Platform Character is a Synthetic lifeform with Digital based mechanics, primarily focuses on Ethurgy, the magic of this stories world. Blue Ethurgy Covers Water Ice Slime & Mist.

Green platform Character is a Cybernetically augmented Lifeform of a Rare galactic species, and utilizes a lot of different Tools, mostly do do with the sky. Green Ethurgy Covers Wind Wood Sound & Sky.

Yellow Platform Character is Biological but fights inside a large Golem Mech, Yellow Ethurgy Covers Earth Lightning Metal & Crystal.

Purple Platform Character is a type of Imitation Robot called a Replica, this one is replicating an Extinct Ethurgy based species, Purple Ethurgy covers Magic Psychic Ether itself and Gravity.

White Platform Character is Biological, he is a mechanical genius and fights using the machines he's made as well as a specially modified purpose Ethurgy Channeler, White Ethurgy covers Light Space Heart & Life.

Black Platform Character is made entirely of Black Innate nanomachines, giving him the appearance of a Shadow Monster, Black Ethurgy covers Dark Toxic Blood & Spirit

Brown Platform Character is a Mechanical being with an extremely advanced Emotional Drive, Brown Ethurgy covers Neutrality, Dimension, Time & Void.

The Red Blue & Green Hearts as well as the Colored Wheel have a purpose in the story itself/