Gestalt Characters are very powerful/versatile characters. Basically they recieve 2 different class levels at each “level up” opportunity. They take the best BAB, saves, hd, skills, and both classes class abilities.
Example – A lvl 1 gestalt character could be a lvl 1 rogue, lvl 1 fighter. This character would have a +1 BAB (fighter), d10 HD (fighter), +2 fort save (fighter), +2 reflex save (rogue), +0 will save (both), 8+int skills (rogue), and class skills would be a combination of both the rogue and fighter. Also, the character would have +1d6 sneak attack (rogue) and 1 bonus feat (fighter).
All player character in this campaign will be Gestalt Characters.