The army of Mara is shown all around the Buddha. Here we see demons, ogresses, seductive sirens, descending spirits, all attempting to prevent Shakyamuni from reaching enlightenment in their own individual way. Mara's power over sentient beings originated from their attachment to sensuous pleasures and the consequent fear of death which lead to intense suffering. Enlightenment would have freed Siddhartha from Mara's control and provided an opportunity for others to free themselves also by emulating him.
Likewise, Mara first sent his beautiful daughters named Desire (Future), Fulfilment (Present), and Regret (Past). The Buddha had already disengaged himself from these pinnings and thus remained unmoved. This prompted Mara to intimidate the venerable one by installing fear in his heart. Towards this end he generated an army of wrathful and hideous creatures, the very personifications of death. But all through the tribulations, Buddha sat calm and unflinching, and Mara had no other recourse than to withdraw, and thus was cleared the final hurdle on Buddha's way to enlightenment.