Please set the display / wallpaper / live wallpaper from Android settings. For complaints and not open there were many, it was added activities that open from the launcher. You may not be able to operate normally after the OS update. Please try to uninstall and reinstall the app once the case.
The download of the app doesn't contain viruses or any kind of malware. Rain of Char Live Wallpaper was originally designed by Siriuth and it belongs to the Personalization category. Over 100K users downloaded and installed this application and its most recent update was on Sep 23, 2018.