If you want information on Zaraki Kenpachi, his page on Bleach Wiki is the best place to find it. Other than that, reading the manga will be the place to get the most complete information. If you wish, you can read the chapter and episode summaries on Bleach Wiki too, if you do not like the character article. There are also the fight articles, such as Zaraki vs Tosen & Komamura and Zaraki vs Nnoitra and Zaraki versus Yammy.