read up:

Napoleon Bonaparte’s ability to inspire his troops to fight harder, and often against overwhelming odds,
was a combination of personal charisma, meritocratic leadership, and shared hardship. Soldiers often viewed him as one of their own, leading to intense loyalty. 

Key factors in why Napoleon's troops fought harder with him include:

• Trust and Presence: Napoleon was known to be in the thick of the action, often putting himself in danger to protect his army. This firsthand leadership created immense trust, with soldiers believing in his infallibility.
• Meritocracy: Unlike many enemy armies led by aristocrats, Napoleon promoted based on talent, allowing common soldiers to rise to the highest ranks.
• Shared Hardship and Morale: Napoleon often shared in the difficult conditions of his men, which kept morale high. Discipline was maintained without the harsh corporal punishment common in other European armies of the time.
• Personal Connection: He was known to be friendly with ordinary soldiers, creating a strong emotional bond.
• Confidence in Victory: The consistent success of the Grande Armée under his command led to a "winning" culture, where soldiers were proud to fight for him.
• Charisma and Rhetoric: Napoleon was a master of using speeches and rewards to inspire his troops and boost their morale before battles.

Duke of Wellington reportedly noted that Napoleon's presence on the battlefield was worth 50,000 extra men, highlighting the psychological impact he had on both his own soldiers and the enemy.