Gareth would have expected to be nauseated by the sudden change in scenery. He was, a little. As he gained his bearings he noticed that he wasn't him anymore. He heard a voice speaking inside his head, the same one that interrupted his conversation. He couldn't tell you what it said verbatim, but he was rather quickly filled with a strange knowledge he didn't have before...
He knew the cards were used to do battle. He saw a black, shadowy figure standing across the swamp from him. His instincts told him that he probably didn't mean well. Time to fight.
The swamp in front of him erupts in smoke, as if it had been set alight. The smoke blows away to reveal a rotted unit of Foul Marksmen. The call of "FIRE!" is heard, and they begin to loose their arrows in an arc.
A Throwing Chakram appears in his hand, and using the marksmen as a distraction, he casts it, attempting to bounce it off a tree and around the marksmen, then into his opponent.
He decides to not use up too many of his resources before he knows what his opponent can do, and assumes a stance optimised for dodging.