Ogichi, or Hollow Ichigo, is the hollow that lives inside Ichigo's power. He is clearly distinguishable in the Zangetsu skyscraper world because of his white clothing, pale skin and yellow eyes. He is part of Zangetsu and Ichigo and because he was originally weaker than the 'Old Man Zangetsu' he was absorbed into him however later in the story when Ichigo needs to rely on him for power he becomes stronger therefor absorbing the 'Old Man Zangetsu'. He is also what Ichigo relies on when he calls his hollow mask. Hollow Ichigo is very Sadistic and loves to battle, in personality he is exactly the opposite of Ichigo.
The Nine-Tailed Demon Fox is the most powerful of the tailed beasts, also considered the "King of the Tailed Beasts". Its power is such that it is regarded as an age-old natural disaster, as a single swipe of one of its nine tails is enough to raise tsunamis and flatten mountains. One of its special abilities is that it has access to close to unlimited sources of chakra. The demon fox's attacks were seemingly random, the only apparent reason for its appearances being its attraction to places of human malice.