There is not much known about the character of Face Changeling.
He likes horror movies, and his hobby is peoplewatching.
In other universes
He is called 'Hemeros Zarate' in the PMMM AU. His appearance is based around 'Feathered' as is seen in the colors and the actual feathers. The artist notes 'he only has one spark in the eye to highlight his power'. This might only be a stylistic difference though.
In the memo, he speaks a few words. At first, he's confused and seems a little bothered about showing up. Knight Vitreous explains what the memo is about, and he understands. He makes a decision not to join, because '[he] heard the stories about his counterpart' and does not like them.
His specific name contains the word 'changeling', but he is not one. It has been confirmed that 'changeling' is merely a moniker humans use, and it is unknown if there is an actual name for it.
He is the oldest character in the dancestor group.
He is the only one whose dancestor, Bonnie, has the same subject number.
His associated color, #0027FF is the inverted form of his dancestor's associated color, #FFD800.