A name format based on the fairytale "Cinderella", where the eponymous character is given a Portmanteau nickname of "Cinder+Ella". Recently "X+Ella" has been a popular way to name some characters. This seems to be even more common for comic books, but it's not particular to them.
It should be noted the the suffix "-ella" is one form of a Latin dimunitive ending; coincidentally, another form is [...] [tvtropes.org]