On the top pic are the Greeds, this show's main villains. From your left, we have: Gameru, Cazari, Mezuru and Uva and as we all know, there is one Greed is missing in the group, namely Ankh who would later give the OOO Driver to Hino Eiji.
Author's Note: Their designs gave me this that it came from an older series, to be exact maybe coming from Kuuga or Agito which is good, plus the Greeds having a belt screams old school to me considering that villains back from the original series wear belts.
All of the Greeds are currently incomplete because of the medals were sealed in various places. They also have mysterious belts.
They have 2 kinds of medals. The one with colors is the Core Medal, it's the core of a Greed's existence. Medals that are silver are known as Cell Medals. These make up their bodies. The Core Medals are like their hearts, souls etc. While Cell Medals are basically like cells in a living thing.
Ankh is a Greed with not that many medals, which caused him to become an arm. This is why he took the body of the policeman. Like all the other Greeds he's collecting medals. To make up for his lack of power, he uses Eiji. What's different about Ankh is that he is sly and sharp sighted unlike the other Greeds.
When they put a Cell Medal inside a human, a monster called Yummy is created. Their source of power is desire. How the Yummies are depends on the Greed. For example Uva's main desire for Yummies are money, wealth etc.
Author's Note: I smell that the final battle is between Ooz and Ankh considering that his description is that he is sly and cunning plus, he is one of the Greeds.
Source: Picture - alternate-zer0, Information - DecaEnd
