Multiple Clients Connecting Through My PC? Don't Think So

I'm really happy with my RT-AC68U. No complaints. But there is this one little thing:

My desktop PC connects to the router with an Ethernet cable. My PC does not have a WiFi adapter. So imagine my surprise when I saw this in my router's network map:



How can 6 clients be connected to my router through my PC? The first time I noticed this, there were 139 clients connecting to my router through my PC. I don't think so. Must be a...

Multiple Clients Connecting Through My PC? Don't Think So