A1. Monster House
The gang is called together to find a beloved town governor and alchemy prodigy, who has gone missing. Turns out he was working with the Church of Mask, using a Spawning Stone fragment to create polymerized monsters to unknown aims. He ended up getting fused with the house after falling into some of his own concoction, after an attack by an unknown force. After he went on a rampage, Lukas destroyed his heart, saving the town.
The gang later determined that unknown force was likely the rogue angel Melahel, who stole the missing Spawning Stone fragment.