Zexion has no meaning in the Japanese language as it's origin is entirely English.
The understanding behind the Organization XIII nobody names is that they are scrambled forms of their original (non-nobody) names, with the addition of X.
Spoilers:
As such, "Roxas" is just "Sora" with an X added. Similarly, "Zexion" is actually "Ienzo" with an added X.
This applies to all Organization XIII members save for Xion, who is neither a nobody or Organization XIII member.
Zexion uses a book called a Lexicon. The name of Zexion's lexicon is "Book of Retribution".
Zexion does not have a last name. Nor does any of Organization XIII.
Zexion is a male character.
if this is kingdom hearts Zexion then no
"Olga" is not a Japanese word or name, so it doesn't mean anything at all in Japanese. Did you mean, "What is the name "Olga" translated to in Japanese?"
Zexion is 16 years old.
Zexion is voiced by Vincent Corazza.
His human's name is Ienzo.
No. There is no relation between Zexion and Riku.
zexion's somebody is ienzo. ienzo is a scientist
The name Michelle does not mean anything in Japanese, but can be written: ミシェル
The name 'Collin' does not mean anything in Japanese, but it can be written in Japanese as: コリン