The creator of comic series The 99 has received death threats from terror group Islamic State of Iraq and the Levant (Isis).
Naif Al-Mutawa's comic, which depicts a group of 99 Muslim superheroes, has been named by Forbes among the top 20 trends sweeping the globe, while US President Barack Obama has praised the creator for his creativity.
However Isis has accused Mutawa of blasphemy, because in his comic series he ridicules Allah's 99 names.
"Who can kill Naif Al-Mutawa who makes fun of Allah's names?" wrote Isis on Twitter, according to Kuwait Times.
"Whoever finds him, kill him, and he will be rewarded."
Mutawa wrote in reply: "My work has glorified Islam from the US to China for the past ten years.
"I really do not believe in ISIL [Isis] and Qaeda... I don't care about them."
Mutawa told Al-Watan daily that he plans to take legal action against the people who called for his death on Twitter.
He also said that Muslim scholars approved of his work, as it does not contain any offence to Islam.
Isis – which recently declared the establishment of an Islamic caliphate spanning Syria and Iraq - is known to use social media for its propaganda. Last June, the group sparked outcry after it tweeted a picture of a beheaded man with the tagline: "This is our ball. It's made of skin #WorldCup."
The group also posted a YouTube video which showed its militants shooting at motorists and pedestrians.
Another video called for support from Muslims, as part of a full-blown "One Billion" social media campaign, with a hashtag in Arabic which translated as #theFridayofsupportingISIS.
Isis' uprising in Iraq and Syria – which started last June – has caused the death of thousands.