User blog comment:Tripletrinityhelixdna/Who or what created the sword of akasha?/@comment-98.28.163.219-20091202191113

It never mentions who made it originally unfortunately. But what we do know is that once Lelouch destroyed it Charles was able to rebuild it, so he must have some kind of know-how on it and maybe he created it originally. Although a few quotes and sources hint at it being there before Charles got Geass.