If you worried about kingroot then it’s work.
www.w0lfdroid.com/2015/05/How-to-Remove-Replace-KingUser-KingRoot-with-SuperSU.html
Just you need to modify the script root.sh
rm /system/app/Kinguser.apk >/dev/null
to
rm /system/app/Kinguser/Kinguser.apk >/dev/null
because it’s android 5.1