Hacka Doll #3 is one of the three main "Hacka Dolls", computer programs that are used to advance their users. He, like his companions, isn't very good at it. No. 3's biggest problem is that he is very lazy and is also an otaku, often playing his portable games rather than actually working. He is called "No. 3-chan" by others but his official profile does call him a trap.
While his normal outfit is androgynous, Hacka Doll #3 gets put into various female outfits to further "advance" his customers.
(Source: Anime Traps Wikia)