So whats the deal in Cantha?

Hey folks ive recently gone from lions arch through to cantha and the whole thing confuses me so i was wondering if i could have a few questions answered.

Whats the main storyline about?
Who is this shrio bloke?
Did i miss out missions by coming to cantha from lions arch?
Do i have to do all the missions before i can get to this kurzick and luxon place?
Why were there 2 parties in the mission i just did?
Also what is this luxon/kurzick thing about?

Thanks for all the help.

1) Finding out what's going on IS the storyline.
2) The emperors bodyguard who murdered the emperor & caused the jade wind 200 years ago.
3) Yes. You missed out on about 2/3rds of Prophecies (the campaign in which Lions Arch is), and one minor island & two missions in Factions (the campaign in Cantha). If you haven't finished Prophecies, I'd suggest going back to Lions Arch and doing that first; if you have finished Prophecies, then you'll quickly find out what's going on in Cantha by doing quests, missions, & paying attention in cutscenes/dialogues.
4) The mission you just did have two teams, one made up by Canthans (with Togo) and one made up by people from Tyria (with Mhenlo). It's just the way the mission is designed.
5) The luxons and the kurzick are two "kingdoms" to the south of the city where you are now, who are at war with eachother. Eventually you'll need to ally with them, and your guild may chose to select one side more permanently.

Well, ive almost finished prophecies, i got up to abbadons mouth then got bored. I've only heard tid-bits about cantha though. Thanks for all the help anyway. One more question though. Whats this jade wind?

It was a sort of curse that Shiro released upon his death. It petrified Echovald Forest and turned the lake surrounding Harvest Temple into jade stone.

Oh thanks... well that helped alot. Im just gonna play the game now and see what happens.