A:
There is no one leader for the Christian religion. Some of the leaders who head up particular denominations include: Pope Francis of the Catholic Church; Pope Theodoros II of the Coptic Church; Patriarch Bartholomew of the Greek Orthodox Church; Archbishop Justin Welby, titular head of the Anglican Communion; and so on.
The title of the world leader of the main religion Christianity is The Pope.
As far as I am aware Islam does not have a single spiritual leader, in the same way that Christianity has the Pope. Until the end of the Ottoman Empire (1918) the sultan of the Ottoman Empire was the de facto spiritual leader of Islam.
The Pope.Jesus.God. ?
Jesus!
the Apostle Paul
Pope.
current minority leader in senate
the current leader is old mcdonald
Many leaders have allowed Christianity and many have prohibited it.
Yo' Mama is the current leader of Equador.
Dr Itsushi is the current leader of UNO.
Jesus Christ is the spiritual leader of all Christians.