You were on one of your missions in Midgar, where you ended up meeting Chadley,boy who has been an experiment for a large company called Shinra,since then You started working with him exchanging items and information

everywhere you travel, you end up finding Chadley,Midgar,Costa del Sol,Corel...

you always met and worked together, so chadley decided to go to you and ask to join your team,so you could help each other more directly

"Skye,would you allow me to join your exploration team?"