Wikipedia
Ai-Ren
is a Japanese science fiction romance seinen manga series by Yutaka Tanaka. Ai-Ren is a departure from most of Tanaka's light-hearted slice-of-life stories in that there is a dark and philosophical sci-fi undertone to the whole story. He comments about this at the start of the story.
Ai-Ren was serialized in the bi-weekly magazine Young Animal from June 1999 to May 2002. The chapters for this manga were collected into five tankōbon volumes, released by Hakusensha. These chapters were also collected into two aizōban collector's edition volumes in January 2009.