Coffee Thief is a Manga/Manhwa/Manhua in english language, Adventure series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

A cafe in the mountains behind the school Rumors spread that there is a 'man who buys time' there. A year ago, 'Yu Narae', who was in an accident, went there with the Grim Reaper, 'Saewoo' and tried to steal time to come back to life..