Mastwick was a coastal town in Drunkeros. Following the events of the Demon Apocalypse, it came to be under the dominion of the dragon Pyre, a tyrannical dictator who made life a living hell for the people living there. It was also the home of the Darkblades, a group of thieves and rogues, who occasionally did good.
Tum Darkblade, Aludra Wyrmsbane, Thom Vidalis, and Junpei Iori visited the place back in 1699-1700. Tum met Footpad Calor, who told him about the Darkblades and Blood Drinker. Also, Aludra won a drinking contest.
Later, the party (minus Tum and Junpei, but plus one Lord Titus Harper) travelled to Mastwick and had an adventure with the Darkblades once again, this time kidnapping Bercy Hamhands and turning him in. At one point Ros goes missing, and she's found in a warehouse, kidnapped by Rugul Thumble, though she could take care of herself thank you very much.
Later, the party (the same as last time, but plus one Jaela, and also Thom had a gnoll living in his head) needed to get to New Newfoundland Land, and the nearest White Spire was in Mastwick, so they teleported there in an attempt to save time and not have to walk so far. Unfortunately, Pyre had locked down the city, and only those with his permission were allowed to leave. So, he made them go on a quest to fetch some Slaadi crystals. Then they could leave the city. Fortunately, they had a new Slaad friend, named Slaad the Slaad! He was promptly forgotten about.
Later, Aludra and Jaela got married, and Steve Meloncamp took Aludra and friends on a bar crawl. One of the places they went was The Foaming Tankard, where Aludra had previously won that drinking contest I mentioned earlier.
- It was revealed in Episode 250 that the walls of the city were being painted red in Pyre's image