Kernel-based
As the name suggests, KernelSU works under the Linux kernel giving it more control over userspace applications.

As the name suggests, KernelSU works under the Linux kernel giving it more control over userspace applications.
Only permitted apps may access or see `su`, all other apps are not aware of this.
KernelSU allows customization of `su`'s uid, gid, groups, capabilities, and SELinux rules, locking up root privileges.
Modules may modify /system systemlessly using overlayfs enabling great power.