Comic Days: Kodansha's official web portal which includes Monthly Shōnen Magazine titles.
While this article aims to help you find the content, it is important to address the legality. Reading raw manga on sites like Welovemanga exists in a legal gray area. The only official way to read Ryuurouden legally is to buy the tankoubon (volumes) from Japanese retailers like Amazon Japan or purchase digital copies from official Japanese e-book stores (which requires a Japanese address and payment method). Comic Days: Kodansha's official web portal which includes