See this page for general information about Septimius Servus. For more details, look at corresponding pages and books about people mentioned on that page (such as
Pescennius Niger and
Clodius Albinus, two of Servus' opponents, among others).
The questions you're asking are all over the place. Some are very easily researched (#3), while others (#6) are more difficult. I don't want to be rude, but perhaps a bit more background research on your part would help answer most of these and help you focus on specifics.
As an amateur history buff, a lover of video games and certain types of anime, I agree wholeheartedly with the sentiment that the media (whether western or Japanese) is terrible at portraying historically accurate information. Even games and movies that actually make the attempt often take creative licenses or make up details when specifics are unknown. And they always make mistakes. Always. Some mistakes are minor (Chinese letters on a lamp), while others are horrible (complete disregard for tactical advantages of guns over swords, because swords are more "cool").
That said, some historical portrayals are a decent enough starting point to begin your research. If you liked Shogun 2, by all means look up the events (
1,
2) in a more reputable historical account. Wikipedia is again another nice place to
start research, and depending on how deep you need to go, that may be all you need.