There’s next to no worldbuilding behind them, but I have a rough idea of what they are. (Or at least VERY VAGUELY what they tend to look like)
Some are more organic than others but they all have squishy blue insides, suggesting they’re at least partially organic. The rest of them is more like silicone and ceramic than metal.
Ekil is the only named one but I’ve drawn some of the others a few times. I guess it’s up to them what they look like. Some have tails, some have little Doctor Octopus arms, they all have different horns and body decorations. Sometimes they even wear clothes! (whoa)
They don’t really have any concept of gender. Most won’t give a flying fuck what pronouns they’re given and won’t know the difference anyway.