Here is a couple of examples:
Shego (Kim Possible), because she was the fifth member of Team Go.
Ultron-5. (The Avengers: Earth’s Mightiest Heroes)
Fearsome Five. (Darkwing Duck)
Fearsome Five. (DC)
Quintessons (Transformers)
Quinton (Formerly, Yu-Gi-Oh Zexal)
The Big Five (Yu-Gi-Oh)
The Fifth Brother
Fatal Five (DC)
Fifth Brother
Negative Numbuh 5
What do you think?