gwen heroes in factions ?

I was fellowing with a guy the other day in factions - He was a level 13 assassin but brought his lev 20 GWEN heroes with him on the mission, which obviously was completed with ease.

How do you do this ? He wouldnt tell me.

Exactly the same way you add Heroes during GWEN quests. Of course, you need to have the full version of GWEN to be able to use the Heroes

You can take any hero you have unlocked on any quest or mission in any campaign.

KANE

Probably he used the special weekend that allowed people between levels 10-20 to enter the Eye of the North expansion to get the heroes.

It's not just in the special weekend..
ANet made it to where you can enter GWEN as soon as you hit lvl 10 and with completion of the first quest you get 2 lvl 20 heros added and then you can also get a 3rd with ease.

well im at lev 15 - got to kaeing centre and I cant get my toon over to gwen. The game only lets me select henchies, not heroes

this is only if you have GWEN or currently have an active trial key.

you need talk to a guy who (if im not mistaken) is nearby the guys who trade you the imperial commendations for other stuff, this guy has the "repair" on his tag name, he should give you a quest to move to GW:EN, but this only happens if you have the game eye of the north on your account.