Originally Posted by
Helden
The Crystal that Jyn wears is a Kyber Crystal (they are the crystals that are used in Lightsabers, attuned to the Force and such), the "2 Asian dudes" as you refer them to, were Guardians of the Jedi Temple (mentioned in the film), the same Jedi temple that was being looted by the Empire to build the Death Star (mentioned in the film), Chirrut (thats the blind fella) still believes in the force, finds a girl wearing a force attuned crystal, the same type that he used to protect in the Jedi Temple (you can draw that conclusion from the things mentioned in the film), and looking for purpose decides to follow her. Baze (thats the other asian fella) follows Chirrut because he has nothing else left in life, he was once a devout follower of the force (mentioned in the film), but the Jedi's defeat has given him a crisis of faith (mentioned in the film).
If you aren't paying attention to the film that you are watching, your not gonna know a characters motivation, i'd say that Baze and Chirrut had quite solid motivations, Chirrut wanted something to follow, some holy quest to go on to hopefully redeem himself for allowing the Empire to loot the temple he's sworn to protect, and Baze just wanted to protect his friend.