Do you wish to read up on the Hokage, or would you prefer the Uruha of which Kurei is in charge of?
Also, you can read about the Shishiten, but beware of spoilers for post volume 16 of the manga.
Info on miscellaneous characters such as Shigeo and Kondo can be found in the Others section.
To make things easier, Kurei et al. are classified under Uruha, and are referred to as "bad" together with Mori Kouran, though we all know Kurei-sama hates his foster father's guts. And naturally, Hokage are "good", though we also know sometimes we all would really prefer the manga to be called Flame of Kurei.
