Someone that lives an isolated life of worship is called a hermit. In Christianity, hermits were originally Coptics that lived alone in the desert. They were called eremites by the Greeks, and that is where we get the word hermit. Hermitage is not restricted to Christianity, it is common in Islam, Hinduism, and Buddhism as well.
Pure devotee
Loner, recluse (or in a religious context, a hermit).
An anchoress is a female anchorite, a person who lives in isolation or seclusion, especially for religious reasons.
An anchoret is an alternative term for an anchorite, a person who lives in isolation or seclusion, especially for religious reasons.
Probably for the same reasons other religious extremists do.
Hermit!
a person who by desire lives alone
Hermit.
Troglodyte
A person who desires to live alone is often referred to as a "solitary" or a "recluse."
recluse
A person who is withdrawn from society and lives alone is often referred to as a hermit or a recluse.
A Hermit.