Please answer the following question: Hen () is a seinen manga which was the first work created by manga artist Hiroya Oku who is best known for Gantz.There are two separate series of Hen but they share the same setting and characters from the first series appear in the second. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
A:
Written Work