Troll often appear in Shadowgate games, guarding a bridge.
Shadowgate/Shadowgate ClassicEditIn the original Shadowgate, the troll is living under his bridge, and comes out to greet Jair, asking for a toll.
When given a coin, the troll leaves, but taking the bridge with him!
Jair fended off the toll troll with a spear, and then using the spell Humana, making himself invisible.
A troll can be found in volcanic caverns under the Dungeons of Kal Torlin, guarding a bridge. He is a friendly sort of green troll. He is bored, only has one job to do, and takes it seriously. That job is to guard the bridge, which he does night and day without much complaint. He will attack anyone who tries to get past him with his club.
Erik is able to speak to him to learn about his job. But needed to get past him to escape the caverns to reach the mountains. He is able to give it a treasure, or a paddle bored (to stop its boredom), or simply punch him a couple of times. The troll is literally a crybaby, and a few punches causes it to sit down, and start bawling its eyes out. Which ever choice Erik is simply allowed to walk by the troll. If Erik returns to the cave the troll appears to be mysteriously missing from its post.
Shadowgate (2014)/Shadowgate Classic MobileEdit
While no trolls appear in these versions of the game, there is a Valley of Trolls shown on the world map for Shadowgate (2014).