The collective name for them is chadics. Examples of Chadic tribes include hausas(*they are different from fulanis), bade people, tumak people and many more. They speak an afro-asiatic language and also possess Haplogroup R1B. The supported theory is that Y DNA haplogroup R1b entered the Chadian gene pool during Baggarization. Basically baggara Arabs inter-mingled with chadic tribes.how did it get there? which ethnic groups have that haplogroup?
You could read more about it with the link below:
Genetic History of Chad (nih.gov)