Why are the translations of 邪王真眼 (jaou shingan) so divergent? In Chuunibyou demo Koi ga Shitai, Rikka refers to herself as 邪王真眼 (Jaou Shingan). Wikipedia says this translates literally to "True Eye of the Evil King". 



A while back, I watched a fansub which translated it as 'Tyrant's Eye'. I'm now watching the official Sentai Filmworks translation, which I've so far been pretty underwhelmed by. The official translation uses 'Wicked Lord Shingan', as if jaou is a title and shingan is a name.

Why are these three translations so different? 'Tyrant's Eye' is easy enough to see; the meaning is close to the literal translation, and it sounds better in English. But why is the official translation so far off?  Is there some ambiguity in the original Japanese that makes this hard to translate? Or did the official translators drop the ball?
The Wikipedia translation "True Eye of the Evil King" is a character-for-character translation of 邪 ja "evil", 王 ou "king", 真 shin "true", and 眼 gan "eye". The fansub translation "Tyrant's Eye" is, as you say, a nice localization of that, where we view jaou ~"tyrant" as an attributive modifier for shingan ~"eye".

Sentai's translation appears to proceed along the same lines: they view jaou ~"Wicked Lord" as attributively modifying this thing called shingan (i.e. what property does shingan have? The property of being a wicked lord, of course). And, in fact, if you were presented with the phrase jaou shingan completely devoid of context, Sentai's translation is not obviously wrong - it could well be that shingan is the name of some being who is a wicked lord or somesuch (in Japanese, unlike in English, proper nouns are not always easily distinguished from common nouns, particularly when it comes to edgy chuuni things). Indeed, one might be inclined to translate it this way as a parallel to structurally-similar phrases like 魔王サタン maou satan "demon lord Satan", where, of course, "Satan" is a name (though in this case there is no ambiguity, since サタン "Satan" is obviously a loanword).

But the phrase jaou shingan is not devoid of context. As anyone who has watched the show knows, jaou shingan is what Rikka calls her eye. As such, it strikes me as bizarre to treat shingan as a proper noun rather than translating it as "true eye" or something similar. 

I think Sentai screwed the pooch on this one.