How to fix sdcard empty under root with Kingoroot? My sdcard is empty when I use su. I have gained root using Kingoroot.
This answer shows the SuperSU solution (mount namespace separation).

How to mount an sdcard to su? What additional information should I provide to get help?

It's a MTK device with Android 4.4.
I never used Kingoroot, so can't be sure if it provides and option for master mount (su mm) or not. You can switch to Magisk or SuperSU once the device is rooted. If you can't or don't want to, you can use:

su -c 'nsenter -t 1 -m /system/bin/sh'


from commandline instead of simple su. This will make you switch to root mount namespace. For details see this answer.
nsenter is usually available as busybox applet.

Since mount namesapce was implemented in Android 6, this might not be the problem with your KK device.

PS:
If Kingoroot works for you, it indicates that your device has some serious security flaw(s). Do consider an upgrade.