|Location:||Abbey of the True Gun|
|The ancient King, protector of the crypt, lives on forever as a demigod.|
The Old King continually follows the player while attacking. His attacks resemble those of the Bullet King, but are more complex. These attacks include:
- Spinning and firing continuous volleys of bullets, each wave alternating in direction. This is followed by a tight-knit circle of bullets, which travels faster and overlaps with the volleys of bullets.
- Firing six spirals of bullets outwards that then return to the Old King.
- Firing four spreads of three bullets to his side.
- Firing lines of bullets in all directions, which then become scrambled.
- Firing a large bullet upwards which bursts into 8 smaller bullets, each of which bursts into 8 more bullets.
- Throwing a flask which causes fire to spread across the room in an X formation.
- Firing many homing skulls, each of which bursts into more homing skulls.
- Firing a ring of jammed bullets outwards that deals a full heart of damage.
- Firing a ring of jammed bullets that chases the player and deals a full heart of damage.
- If the Chancellor is hit with Casey from about a Casey's length away, the Chancellor's body will deal a large amount of damage to the Old King, killing him in one hit.
- If Old King is jammed, he will have enough health to survive this and will be left with around a fifth of his health remaining.
- Defeating the Old King for the first time unlocks the Bloodied Scarf.
- Unlike Bullet King's Chancellor, the Old King's Chancellor won't try to kill the gungeoneer in the next boss battle if left alive.
- After A Farewell to Arms, defeating the Old King will reward the player with a synergy chest.
- Before the Supply Drop Update, the Old King had the same splash screen quote as the Bullet King.
- This boss is a reference to Old King Doran from Demon's Souls; not only is he an "Old King", he defends a crypt as an optional boss. Doran also drops the Eternal Warrior's Ring - the description reads as follows: "The hero Doran, protector of the royal family of Boleteria, lives on forever as a demigod."
- His name and attack patterns may be a reference to the Bullet King in the beta, as there are images where he is shown to throw a flask that spreads in an X formation much like the Old King.
- The Old King has a Bullet Kin next to him that, like the chancellor in the Bullet King boss fight, will chase you around if shot.
- The Chancellor's base health is 1000 (and since the Chancellor is in Abbey of the True Gun, its health is multiplied by the floor's health scaling, which is 1.6666...), and the damage done to the boss when you blast him with Casey is 1000 x 1.6666... x 2 = 3333.33.... Interestingly, this is higher than the Old King's health by only a sliver.
- The design and fight patterns of the Old King, in addition to his location and the theme of the Abbey, seem to suggest he is the previous Lead Lord. The design of the Abbey, his throne room, and the vast difference in difficulty also suggest he was a much fiercer ruler.
- The gargoyle-like statue heads decorated behind the Old King resemble that of the two demon statues seen just before the boss fight against Doctor Wolf's Monster.
- The physical Ammonomicon shows a doodle of the Old King being pushed off his throne by Cannon and Agunim, meaning that the Old King had met Agunim at one point before being defeated by the wizard and retreating into the Abbey of the True Gun.
- The Old King is the third most durable boss in the game, having slightly more health than the High Dragun (not including his Advanced Dragun phase), but has less health than the Lich and the Resourceful Rat.