Great question! Tobe is of course the one servant that Miss Emily retains throughout the latter stages of her life after her father dies. He is a black man-servant, and because of this, it is something of a minor scandal that she allows him to look after her housekeeping. He is blamed by the ladies of the community for the stink that emerges from the house after the disappearance of Homer Barron. As the only person that Miss Emily spends any time with, he is very secretive, keeping the murder of Barron as a closely kept secret and rarely speaking to anyone. After being the only witness to Miss Emily's death, he opens the house to the townspeople before vanishing himself:
The Negro met the first of the ladies at the front door and let them in, with their hushed, sibilant voices and their quick, curious glances, and then he disappeared. He walked right through the house and out the back and was not seen again.
His character is interesting because he is the one person who remains loyal to Miss Emily, but because of the racial divisions of the old South he is never able to be a friend to her. His disappearance from the tale at the same time as Miss Emily's death seems to symbolise the passing of the old order of the South that Miss Emily seemed to symbolise, and thus in response to your question I think he is related more to the South than the North.