During our game yesterday we came across this little issue..

is the Goblin sapper ( STRANGER - pay him 1 gold and move him to any space with a face up adventure and destroy the adventure card on the space ) a 1 time use or does he sits and wait on the space he was moved to for the next adventurer to come by and use him again?

The Gobling Sapper waits in the space for someone else to use him on a future turn.