Urotsuki (うろつき) is the protagonist of Yume 2kki, which is a play on words. (2 is pronounced "ni" in Japanese. Thus, Yume Nikki=Yume 2kki). There is little to no information about Urotsuki and her relationships with other characters, but it seems she knows (or knew) many people due to the large amount of humanoid characters in the game.
There are multiple theories about her, such as she suffers from manic-depressive syndrome (bipolar) or another personality disorder. Different portrayals of her in the game show that it is likely she changes personalities quickly towards other beings. The three more popular males of the game are hidden away as if to say they are past memories or loved ones. There has been no hint of any relatives in the game except for a male who sits and holds a cup between his legs and has a similar hairstyle and color to her own.