Wearing a cape and a smile, the Pope has joined the legion of superheroes in a Vatican-approved comic book.

The first issue of the real-life and adventures of John Paul II's fight against evil has sold out. The religious publisher Paolini is considering translating the four-part serial into other languages and selling it abroad.

Critics in the Vatican are afraid that it will demean the church and reinforce a cult of personality.

The Little Paper, an illustrated children's magazine, appeared on newsstands last week with the first installment of the strip "Karol Wojtyla: Pope of the Third Millennium".

Opening with his election to the papacy in 1978, it features a larger-than-life John Paul dominating St Peter's Square with white smoke swirling above him. "Our commitment is rather grandiose, dear children: telling the life of no one less than the Pope," the introduction says.

The story is told in flashback, with dialogue in bubbles, by a grandfather who is asked by his grandchildren why he is not pope. He explains that the ailing 80-year-old, who trembles from Parkinson's disease, was once a sports-mad boy called Karol who grew up in the Polish town of Wadowice.

"I got it!" shouts a knobbly-kneed Karol as he blocks a goal during a football match.

To children too young to know that the Pope has long been known as God's athlete, it is a revelation. Grandfather recalls that Karol never felt compelled to prove himself by smoking, boozing or staying out late.

The some-time amateur actor is also shown with an oversized moustache playing opposite a gorgeous leading lady in a costume drama.

"Whattttt? You want me to believe that he acted with girls?" Grandpa is asked. "Certainly," comes the reply. "And danced the waltz, the mazurka and even the tango."

The comic strip also shows Karol losing his mother and only brother by the time he was 11 - traumas which proved decisive when forging his personality.

Written by Alberto Bobbio, the comic is a sister publication of the Catholic magazine Famiglia Christiana. It follows other Vatican innovations in reaching out to young people, such as the recording of the Pope's hymns, which went platinum.

According to Italian newspaper La Repubblica, "more sober" elements in the Vatican think putting the pontiff on the same sort of level as Superman and other superheroes is a mistake.

"They turn up their noses," it says, "but they do not speak out, because to criticise in these times causes trouble."