Weird app keeps installing in my Nougat

[Lud_wig]

Hi guys. I've been having a problem with ads popping up on my screen every now and then. I looked for different ways to get rid of it and I ended up finding a weird app on my phone that's named "com.android.ftree.artest" I uninstalled it for like 3 times, but when I see and ad pop up on my phone again, I just find it installed on my phone on the apps tab in my settings. Its also disguised on the "system apps" category.....This is probably w virus. I would appreciate any help. I already tried safe mode and bunch of antivirus apps. Nothing works