55, or Five-Five, is a Zeroid of the Terrahawks. While he is under Sergeant Major Zero's command on Earth, he spends the majority of his time accompanying Captain Kate Kestrel, both on missions and on downtime, pitching in with song lyrics she may be struggling with. 55's personality quirk involves him almost always speaking in rhyme, though this trait doesn't annoy people as much as some of the other Zeroids' quirks.