It's part of Tri City Monsters- this is the "final" version of Mori's intro so it has more content and polish than the older version. Since the older version was the "prototype" it was retired/taken down. (Though you can still play that older version on Gamejolt if you like)
Basically, this page will have whatever chapter is newest and each character will have their own page as they get content. Edit: I misspoke, sorry, THIS page will always have Mori's chapters, and the new 'main page' will always have the most recently released chapter regardless of character. SORRY if that's slightly confusing right now, it's for organizational purposes down the road once we have 6 characters with multiple chapters each.