Or, in other words, you don't translate names.
You would find, if you took the time to look, that most names have original, obscure meanings; it's the nature of language that words mean things, and the nature of people to create names with meaning.
More importantly, however, Cape Names almost always have meaning, and are intended to carry some significance since they are intended to say things about the one using them, not just be a label. Normally, I would leave it at "Wildbow is an idiot" or at most "let's confuse things by using words from different languages" as an explanation, but in this story, that no longer fits.
It has been mentioned, specifically, that Oni Lee uses Kanji to write out a note, and uses a Kanji that can be translated as "Plum" as the character for "Lee". If he was trying to confuse things, he would have used a mix of writing systems, not pure Kanji. Further, the Author of this story is not an idiot. That just leaves the combination of characters used as having a specific meaning of significance. Otherwise, the translation of that Kanji would not have been offered in the first place.
So, I know any specific creature from folklore in a culture will be the product of that culture and no other, but I have come across several things over the years that equate "Oni" with terms like "Ogre", "Goblin", or "Demon". In First Edition AD&D, Oni was an alternate name given in the appropriate source books for the "Ogre Magi" in the Monster Manual. This is why I went with "Ogre Plum" as a translation.
So, I know what a Panacea is. I understand what the Aegis was. Glory Girl's meaning is rather clear. Kid Win is easy to understand. So, with the knowledge that the Kanji in his name means "Ogre Plum", what is the significance of Oni Lee? What does it mean? Does it have any importance whatsoever, or is the Author just stuck with Wildbow's bad decisions and trying to make the most of it? That is what I would like to know.....
Wildbow probably did what I did and fired up Google Translate. Except, back in the early 00's and 10's, the results were somewhat more humorous.
Oh. So, no meaning whatsoever. Well, I feel a bit foolish now.......