Castle MacFrights is the sixth floor of The Last Resort in Luigi's Mansion 3. It is accessible after capturing Amadeus Wolfgeist at The Great Stage and obtaining the its elevator button. This floor has a medieval theme and prominently features suits of armor and traps such as spikes and swinging blades. Upon arriving here for the first time, Luigi nearly gets hit by a falling axe. In order to get through the Front Gate, Gooigi must walk through and pull the nearby rope to open it. After reaching the Coliseum Balcony, and a fanfare played by two trumpet-playing Goobs, Luigi is discovered by the castle's ruler and namesake, King MacFrights, who taunts him with the next elevator button and dares Luigi to reach him.
On his way to the Coliseum, Luigi encounters Goobs with swords, Goobs with shields, tomato-throwing Oozers, Mini Hammers, and Mini Goobs. At one point, Luigi gets trapped in a dungeon cell with two spiked walls closing in on him. Gooigi must defeat the ghosts in the room and pull the rope that opens the cell door so Luigi can escape. Once he reaches the Coliseum, he is challenged to a battle by King MacFrights. He gets inside a suit of armor and rides around the arena trying to hit him with his lance. After slamming his armor enough, it breaks and he can capture the king, who drops the elevator button he was holding. With this, Luigi can access the Garden Suites.
||One of the suits of armor is holding a bag of popcorn with the gem in it. Luigi must capture King MacFrights before he can access it.
||Hall of Armor
||Using the Dark-Light Device to reveal the missing suit of armor on the right then slamming it reveals the gem.
||Luigi can use the Suction Shot to open the barrel on the right, which contains a hidden path to a ladder, which leads to the gem.
||Luigi needs to vacuum the rightmost tapestry of King MacFrights in the Coliseum Hallway, then use the Dark-Light Device to reveal a door. The door leads to the Royal Coffers, which contains the gem.
||Using the Suction Shot on the set of bricks in the middle that stands out reveals a treasure chest containing the gem.
||At the bottom of the room, the wall on the left has a fan that Luigi can blow exhaust on to lower a cage that contains the gem. After lowering the cage, Gooigi can walk through it and get the gem.
Names in other languages
||Mystery Manor ("Misteryo" is a distortion of "Mistero", which means mystery)
||McAbre Castle, pun on macabro (macabre).
||Fearieval Castle, pun on miedo (fear) and "medieval"
- Tomatoes are stored within many of the rooms in Castle MacFrights, referencing how people in Ancient Rome would throw tomatoes in the Colosseum if they did not like the performance.
- Castle MacFrights resembles the real-life family dinner theater, Medieval Times.