We're actually a system of 3! Have been. For a very long while.
The 3rd headmate is 5c9e, and likes going by the nickname 'Niney'
Its pronouns are strictly it/its, and refers to itself in 3rd person (Example: "it likes colors" instead of "i like colors")
And of course, it's a robot.

Why haven't we talked about it sooner? Well, it's shy for one, and furthermore, it's not really active much of the time compared to us other two.
Regardless, it's important and has been wanting to be included somewhat more than usual.

All that said though, please don't come in our dms/notes/comments and start asking questions about it.
It's shy and only really wishes to interact with those it's comfortable with. Give it time.