Thread for this series about a magical princess sent to Earth who teams up with a boy to fight monsters?

There's those comics meant to learn English, a 52 episode animated series, and even a musical, but guess nobody here knew about it till yesterday.

https://www.youtube.com/watch?v=AkOwiDfjC3w
https://www.youtube.com/watch?v=e6Iwa5pAtls
https://www.youtube.com/watch?v=hEQot_f4q0I
https://www.youtube.com/watch?v=NwJNj4brT9s