The death of Idriss Deby: What next for Chad after president killed on frontline?

What are the chances in 2021 of a world leader dying on the battlefield? Chad's leader of 31 years succumbed to his wounds after once again going to the front. Idriss Deby was one of those African strongmen that seemed to have nine lives. He had gone to face down yet another rebellion or foreign incursion, this time an uprising in the centre-west of that sprawling Sahelian country. Deby's death at 68 was announced one day after coasting to another easy re-election, this time with almost 80 percent of the provisional vote. So whodunnit and why?