What do different schools of Buddhism say about Mara
Mara , according to the specific Buddhist and Hindu Cosmology, is the leader of the heaven above Sakra, prince of the Devas (see The Thirty-one Planes of Existence).

According to Wikipedia's Mara (demon) article:


  In Mahayana Buddhism. There are traditionally 
  these four types of Mara
  In traditional Buddhism, four metaphorical forms of "māra" are given:
  
  
  Kleśa-māra, or Ma̋ra as the embodiment of all unskillful emotions, such as greed, hate and delusion.
  Mṛtyu-māra, or Māra as death.
  Skandha-māra, or Māra as metaphor for the entirety of conditioned existence.
  Devaputra-māra, the deva of the sensuous realm, who tries to prevent Gautama Buddha from attaining liberation from the cycle of rebirth on the night of the Buddha´s enlightenment.
  


This Devaputra Mara is, according to Buddhists, a real sentient being.
He is destined to become a  Pratyeka Buddha. His followers might not be so fortunate.





The above image quoted from The Thirty-one Planes of Existence. Note especially:


  
  Realm: 11) Devas Wielding Power over the Creation of Others (paranimmita-vasavatti deva)
  Comments: These devas enjoy sense pleasures created by others for them. Mara, the personification of delusion and desire, lives here.
  Cause of rebirth here:
  
  
  Ten wholesome actions (MN 41)
  Generosity