A hermit, or just lonely.
hermit
A hermit is someone who lives secluded from the world. They usually live alone but they may have a partner or companion.
Lone wolf
Charlie Sheen? Or a hermit.
Hermit
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.
Someone who lives in Haiti is called a Haitian.
Someone who is antisocial and lives alone. They would like that life too.
quirkyalone
This is called an autocracy.
It is called a solo. The texture is called 'monophonic' texture (it means "with no accompaniment").
an alien