- Leon and Lola have been described as "siblings" by the media and by Zero-G themselves. It has never been established though.
- Meiko and Kaito are counterparts to each other
- The Kagamine's are "twin" voicebanks.
- Prima and Tonio are confirmed partners and confirm "not married" by Sonika's twitter.
- Ann and Al were designed to both be frankenstein monsters and counterparts to each other.
- Kiyoteru and Yuki are counterparts.