The young general appeared timid, his gaze fleeting, when the army announced his father Idriss Deby Itno was killed en route to the front line against rebels on April 20, 2021.
Deby Itno junior was not on any list of heirs to the throne drawn up by experts, who believed the veteran warlord and president seemed to worry little about anointing a successor.
Three years on, the 39-year-old is following in his father's footsteps as the desert state's new strongman, announcing his bid for a May 6 presidential election with the opposition muzzled and his main rival killed.
But not all is well: the head of state's legitimacy within his family and Zaghawa ethnic group has been shaken following the killing of his cousin and main rival on Wednesday.
Cousin killed
"The man in black glasses," as he is known in military circles, is said to be a discreet, quiet officer who looks after his men, though the public knew little about his past and personality in 2021.
Deby Itno immediately took charge of a transitional military council and appointed 14 of the most trusted generals to a junta to run Chad until "free and democratic" elections would be held within 18 months.
His extension of the transition by another two years sparked major protests in October 2022 that were brutally repressed by the police and the army.
Opposition figures have fled, been silenced or joined forces with him, while any attempts by civil society to form movements, protest or come out against the military rulers have been eliminated.
The killing of his cousin Yaya Dillo Djerou eliminated the main opposition figure from the May 6 vote in which Deby Itno initially said he would not run.
The election now appears a formality that will further entrench the Deby dynasty's domination.
But his cousin's violent demise and the arrest of an uncle, Saleh Deby, has deepened fractures within his family and the Zaghawa ethnic minority that has long dominated Chadian politics.
To assert his authority, Deby Itno has removed several generals who had remained loyal to his father.
Rumors have surfaced in recent weeks of an attempted coup by soldiers previously close to his father or allies of Dillo and Saleh Deby.
All-powerful guard
Commander in chief of the all-powerful red-bereted presidential guard, or DGSSIE security service for state institutions, Deby Itno carries the nickname Mahamat "Kaka" — grandmother in Chadian Arabic — after his father's mother who raised him.
A career soldier, just like his father, he is from the Zaghawa, which can boast of numerous top officers in an army seen as one of the finest in the region.
Born to a mother from the Sharan Goran ethnic group, he also married a Goran, Dahabaye Oumar Souny, a journalist at the presidential press service.
She is the daughter of a senior official who was close to former president Hissene Habre, ousted by Idriss Deby in 1990.
Deby Itno was sent to a military school in Aix-en-Provence in southern France but stayed only a few months.
Back home in Chad, he returned to training at the military group school in the capital N'Djamena and joined the presidential guard.
Rising through the ranks
He rose quickly through the command structure from an armored group to head of security at the presidential palace, before taking over the whole DGSSIE.
Deby Itno was acclaimed for his efforts at the final victory in 2009 at Am-Dam against the rebel forces of Timan Erdimi, a relative.
Those forces had launched a rebellion in the east and had reached the gates of the presidential palace a year earlier, before being pushed back following French intervention.
He finally moved out of the shadow of his brother Abdelkerim Idriss Deby, deputy director of the presidential office, when he was appointed deputy chief of the Chadian armed force deployed to Mali in 2013.
That brought Deby Itno to work closely with French troops in operation Serval against jihadists in 2013-14.
LIBREVILLE —Emerging from the shadows after his father's three-decade rule over Chad, Mahamat Idriss Deby Itno is poised to consolidate the family dynasty in a presidential election where victory seems inevitable.
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