For some who didn't know, there is actually a mangarock Definitive instead of normal mangarock from playstore. Here you can read all manga that is not available on playstore.
I downloaded the mangarock's beta version, you can choose which source you'll get your manga(mangarock,kissmanga,mangafox, etc.) I use mangarock as source and the mangas that aren't available in the playstore version are there. Is what I downloaded the definitive version?
Actually I feel bored finding another manga now. And that result to me for not using mangarock or not reading any manga. I just wait for updates to my favorites
In definitive you can also download art pieces. I've found such good background pictures for my phone. And yes there are a variety of themes, like ecchi, nature, schoolgirl etc. They have att pieces with popular manga too! Its definitely worth getting.