Nairobi – The unexpected death of Burundian President Pierre Nkurunziza plunges the country into uncertainty, opening up the possibility of power struggles in the upper echelons of government.

Evariste Ndayishimiye, elected last month to replace Nkurunziza, is on the frontline as the country navigates its latest challenge.

While he is also a general, Ndayishimiye is not a regime hardliner and Nkurunziza was expected to continue to play a significant role, possibly limiting the independence of his successor who is reputed to be more tolerant and open.

The timing of Nkurunziza's death, just days after the final election results were confirmed, is in some ways a blessing, said Tertsakian.

After years of repression following the 2015 crisis in which Burundians were killed, tortured, imprisoned arbitrarily or disappeared, Nkurunziza leaves a "dark and sad legacy" in a country "gripped by fear", said Tertsakian.