Question about this Ariel Doubleblade character

After a 5 year furlough I have returned to GW. Much has changed but I am attempting to get back into the flow of things.

Anyway I was attempting to do my solo farm in the North Kryta Province. Launching from Bergen Hot Springs I make my way north, but then out of nowhere this Ariel joines my group with her spider pet. Only mission I have is Mhenlo's request.

How do I get rid of her?

Thank you.

Welcome to the War in Kryta. You will also notice higher level White Mantle and Peacekeepers scattered around Kryta. Random Shining Blade allies will join you as you zone.. and no, you can't rid yourself of them as they self rez.

You must have finished Proph or EoTN and enabled the WIK content.

http://wiki.guildwars.com/wiki/War_in_Kryta

did you start wik? dunno how you could have with such long absence from the game, but it is the only thing I can remember her joining party so it is my best guess.
In that case her or other allies will join you when you enter krytan areas. only way to get rid of those is finishing wik, meaning doing battle of LA.

Pretty easily - if they had beaten Prophecies before taking a break, then WiK would be triggered once they returned.

Side note: You're most likely confusing 2 sets of allies.
Their isn't one named "Ariel", but there is one named "Alari". She's an Assassin. Then there's Shadow (ranger) and her pet spider Carlotta (assassin).

You must complete "The Battle for Lion's Arch" which is part of the War in Kryta, mentioned above.

Until you complete TBfLA, all Kryta zones (Black Curtain, Nebo Terrace, etc etc) will feature Peacekeeper-style enemy spawns and usually at least one Shining Blade ally spawn. Once you complete TBfLA, the extra NPCs (both friendly and hostile) will no longer appear in Kryta zones.

was not aware of that... thought you had to have seen some of all those conversations and stuff for it to start.
In that case it makes more sense to me

anyways as already said, battle for la needs ended before those allies and foes go away.