Al Turabi is the man who brought Shariah and Osama Bin Laden (they're related by marriage) to Sudan, before his former ally, Bashir, ran them out. He also tried to kill Mubarak. If Bin Laden is the Saudi Arabian face of AQ, Ayman al Zawahiri the Egyptian, Turabi is often called the Sudanese wing, or the Sudanese Taliban. He's allied with the Justice and Equality Movement in Darfur, the primary insurgent group there and fellow Islamists. If he makes a return to power it'll be spectacular.
Since snubbing the US, the PRC has been Bashir's foreign backer, allowing their national petroleum corporation to operate on Sudanese oil reserves. But without South Sudan, he's lost +80% of said oil to a new American proxy state, and Beijing is dissatisfied with him. A Turabi regime could unite the Arab Sudan and Darfur against the Christian-Animist pro-American south, draw in tens of thousands of foreign jihadists, and retake what Bashir fumbled.