Location: The Hideaway (ship)
Petitioner: Owain, Engineer
Unlocked: Complete Letting Off Steam
Reward: Treated Potion Satchel, Black Blood, 40 Renown
In order to unlock this side quest you need to progress far enough into the main story to reach Out of the Shadow. The majority of Out of the Shadow consists of three sub-quests, all called Letting Off Steam. Complete the three parts of Letting Off Steam, unlock the next area, and visit it once to gain access to all of the side content, including Weird Science.
Check in Mid's Dungeon, below the Atrium, and you'll find an engineer named Owain. He's busy working on an alembic, used for filtering and distilling liquids, and he needs some assistance. Apparently the ashes of a Bomb King are needed to operate one, and there just so happens to be a Notorious Mark who would fit the bill.
Check in with Nektar in the Mess and you can ask about Bomb sightings. This will add the Bomb King to the Hunt Board. The Bomb King resides in the Crock, a small side area in the south of the Dragon's Aery. Jump to the Dragon's Aery Obelisk and head south, following the treeline on your left, until you start seeing Fallen ruins. There's a gate ahead that will bring you to the Imperial Chase, which leads to a building called Heavenhall. Just outside the walls of Heavenhall is a path leading north, which will take you to the Crock.
Monarch of all Bombs, the Bomb King won't go down without a fight. It uses the following attacks:
- A fiery, body-slamming charge
- Fast-moving spitballs of fire
- Slow-moving, blue spitballs of fire that appear in clusters
- A plume of fiery breath with a short range
- Coronation, which lobs a fire bomb that leaves behind a long-lasting pool of flame - creates multiple pools later in the fight
- Witan, a slamming AOE attack that creates multiple doppelgangers of the Bomb King
- King's Justice, a flurry of fire bursts from the Bomb King and its doppelgangers, all aimed at Clive
- If you want to stick with close-range attacks you'll want to use either Phoenix Shift or Lunge to keep up with the Bomb King. Sweep up and use an Eikonic Ability or two before the Bomb King retreats. Coronation is a good opportunity for this, as the Bomb King will spit right over your head.
- If you'd rather fight at a range you'll want a suitable Eikon, and earlier in Final Fantasy XVI your choice will be Ramuh. Normal ranged blasts via the Triangle button are also quite handy. Once the Bomb King tries to charge Clive you can switch to close attacks.