Weiss Schnee

White is one of the main characters in RWBY. She has yet to make an appearance. The White trailer will be released on Valantines Day.

Speculation
Note: The following information is fan speculation, and is not to be considered canonical.

The lyrics in the song Red like Roses, along with Red's strong resemblance to Red Riding Hood, have led fans to believe that each of the main characters is based on a popular fairy tale. This theory was later put to rest by the creator Monty Oum when he assured his fans that these character's would NOT be based on any Fairy Tales. Miles Luna also said that the white trailer would be coming "soon".

Fans have speculated that White's weapon is a sword/shotgun combination parallel to Crescent Rose's scythe/rifle, but this is based on an interpretation of of her title card silhouette, which has also been fan-interpreted as an umbrella or parasol. Recent screenshots of a White 3-D model have implied that White's weapon may have rapier elements, with a thin, pointed tip; no further information either supports or debunks a firearm capability for this item.

The first line of Red like Roses ("White is cold // and always yearning") implies some thematic association with the element of ice, isolation, loneliness or emotional distance.

The second line of Red like Roses, specifically "burdened by a royal test" seem to imply White has some previous connection to a royal family (perhaps a specific member, or that she herself is a royal) and has yet to complete a given task, or undergo a specific trial.