Guild Wars 2

The ‘Hydra Head’ mob was just floating mid air.
[image for referance]

Hello,
So a friend who does not own the game yet but wishes to get into playing asked, if they prepurchased HoT (with the core game) will they be able to begin playing the core game immidiately after purchase?

I did not know the answer to this so I thought I would pass it on to someone who possibly did.

Thanks.