Board Thread:General Discussion/@comment-6192846-20150805165545/@comment-6192846-20151222191003

Yes, the name is ヤーコ (Yaako), so it's Japanese pronunciation is with a Y at least. Sometimes pronunciations differ for various reasons when translated (Yanusu -> Janus) but that's the original Japanese we're working with. Hence why I want to explore slavic or even germanic names where a Y sound can be spelled with a J.

I couldn't find anything justifying "Jack" as a translation though. Like Jacques, that name uses ジャック (Jyakku).