Thread:Xehvary/@comment-27754788-20131009210302/@comment-5716969-20131010225645

Eh their translation isn't official, it's incorrect. Besides everyone agrees that the accent marker is just fine. It's the most consistent and this isn't the first time aniplex fails to get a character's name right :/

As stated before, either Ryūko or Ryuuko is correct. Her name has an accent marker on it officially and I'm pretty sure the accent marker would indicate another U.