Tanya Denali is a character from the Twilight Series. She is trying to get Edward for herself. For this reason Bella hates her. In most Twilight Fanfiction, Tanya is the female antagonist, trying to steal Edward from Bella. The term Tanya can be applied to whores/sluts/skanks that are trying to steal your boyfriend.
OMC she is such a Tanya Denali