combining mouse movements with arduino movements

for a while now i’ve been trying to figure out how this would be possible. i would like to combine my arduino and mouse together. i have x and y cords pumping into my arduino via usb to ttl, then using those cords to move my mouse on my main pc accordingly. this works great… but i would like my arduino to take mouse input aswell.

tldr my end project is to combine my arduino mouse movements and my actual mouse movements into one.

side note: the reason i am doing this instead of using a usb hub is i want it to show up as one device on my main pc.

sorry if this is a hard read, wrote it pretty quickly and on mobile. only reason i’m making a post about this is it’s difficult to word, and google.