I understand that a lot of the people existed but I don't know to what extent. Thank you for knowledge.
There's quite a few threads that have covered this and related topics. you might be able to get a satisfactory answer from one of em.
http://www.reddit.com/r/AskHistorians/comments/2rut9h/accuracy_of_romance_of_the_three_kingdoms/
http://www.reddit.com/r/AskHistorians/comments/pcxbj/the_romance_of_the_three_kingdoms/
http://www.reddit.com/r/AskHistorians/comments/rt0ah/how_accurate_are_the_events_portrayed_in_the/
http://www.reddit.com/r/AskHistorians/comments/2jv5fp/what_do_we_actually_know_about_lu_bu/
http://www.reddit.com/r/AskHistorians/comments/2qqh10/i_have_played_the_game_dynasty_warriors_and_i/