While you're out hunting for rare and unique weapons in the vast wasteland that Fallout 4 brought to us, you shouldn't forget about the Shishkebab. This flaming sword can be found at Saugus Ironworks, in the North part of the map. From there, you'll find it in the Blast Furnace, carried by Slag.
If you're taking a break from the game, you can still bask in the light of the Shishkebab. The latest episode of Controlled Chaos with Caleb, on the Make YouTube account, Caleb Kraft showed off his Shishkebab build. That's right – the flaming sword really exists now.
Using a Katana, a motorcycle's brake lever, a propane grill igniter and a ton of other items Caleb managed to recreate the Shishkebab, have it function like it does in the game and painted it to match concept art. Not only did he make the sword, but he even used it on things… Which is exactly what you do when you have a flaming sword.