Talk:Leonardo Watch/@comment-108.170.159.190-20150416200104/@comment-26323449-20150423035141

The reason the official website writes "Leonardo" is due to the direct romanization of the katakana. The Japanese alphabet always ends syllables in a vowel, or 'n' sound. For example, Vash's name, ヴァッシュ, would be romanized to Va-a-Shyu.

Since "Leonardo" is most likely an English to Japanese representation of the English name "Leonard", translators typically would drop the 'o' and go with Leonard. But technically, it's up to the discretion of the author himself. For all we know, the author could have fully meant Leonardo.