Terra is a fictional character associated with the Fate series name provided by the user, but there is no widely established canonical Fate character commonly known simply as Terra in the main anime or visual novel continuity. As a result, the safest identification is the name itself rather than a confirmed surname-based full name. If you are referring to a specific spin-off, fan work, or localized adaptation, the character may have a fuller official name, but it is not consistently documented across the franchise.