Constellation:

Character:

Yuki is a bibliophile humanoid interface created by the Data Overmind, whose responsibilities involve monitoring Haruhi and the investigation of an unexplained "explosion of data" three years prior to the present story. She possesses an ability to manipulate her surrounding environment. Yuki is very quiet, but can speak at length when it has to do with her mission or a problem that has arised. While she always seems to be engorged in her reading, she comments that she is only relatively interested in them. Yuki gives hints and aid to Kyon throughout the series.

Source from Wikipeida