Guild Wars 2

It’s a pretty involved event that rewards with loot and a merchant (if you hold all 4 locations) that will trade you karka shells for stuff, will the entire event remain after the conclusion or are you going to take away parts of it?

It seems that it starts with rampaging wildlife (that clue is tucked nicely into a bullet point of the Canach solo instance info btw) and has multiple outcomes.
While I’m here, how do you pronounce Canach? ch as in ‘k’ or ch as in ’ch’eese?

As per https://www.guildwars2.com/en/community-news/a-guide-to-last-stand-at-southsun-cove/
“Four settlements (Point Pride, Kiel’s Outpost, Steampipe Steading, and Camp Karka) are integral parts of trade on the island. If all four camps are held by the players, a special merchant will appear on Pearl Islet to exchange armor for karka shells.”

I like that he’s like the gw1 armor collectors

How can it stay? It will be around for a while, but eventually the deal with Canach’s rampaging critters will clear up, at which point the camps won’t need to be saved. It’s possible that they will put in something else at that point, though, to continue it all, who knows.

They already said it will be a permanent repeating thing, like all the other world bosses

Yes. It’s a new meta-event so that there is a reason to go to Southsun even when the event is over.