The Duke of Flies is a boss that is often encountered early on. He never charges at the player, seeming content to drift around the room in wide arcs, vomiting up clouds of Flies to act as a protective screen, as well as Attack Flies. He also has a relatively low amount of health.
He coughs out regular Flies and Attack Flies around him and floats around the screen in random directions. However, he will typically move away from your shots.
- If you do not shoot him, he will keep bouncing off the walls.
- If you do shoot him, he will "bounce" away from your shots (to a degree).
- He will cough out regular flies for defense and will keep doing so if you continue destroying them. These flies will circle around him.
- If he has too many flies around him, he may "release" some of them, which will proceed to attack the player.
- Once he has sufficient defensive flies, he will proceed to spawn attack flies instead, which are stronger and poised to attack the player from the start.
- He has three distinct mouth sounds and if you listen carefully, you can learn their meaning.
- One sound for spawning defense flies.
- One sound for spawning attack flies.
- One sound for releasing some defense flies to attack you.
Actually getting your shots through to him is the most challenging part of this encounter, and that can be accomplished in a few main ways:
- Circle around until you line up on a gap in his fly screen and lay down a volley.
- Punch through his screen with bombs/Mr. Boom.
- If you have The Sad Onion or Number One, simply concentrate fire on the Duke and let the sheer volume of shots take down the flies.
- A single bomb will kill him in one hit, in most cases.
- Using the The Hourglass on the Duke makes him spawn six Flies instead of three.
- The boss gets significantly harder if you can't land your shots right away. The green champion variation is particularly dangerous as shooting down Moters will make it very easy to get hit.
- When The Duke of Flies starts spitting up Large Attack Flies, focus-fire them down when they appear to keep things under control.
- If you get swarmed by his Flies, it is always a good idea to leave the Duke alone and concentrate on his spawns. While this will not damage the Duke in any way, one tends to overlook the Flies often before they become too much to handle.
- Another good tactic is placing a bomb next to you and using your tears to send it directly to him. This is pretty useful against champion versions, as the bomb can easily take out the monsters spawned and deals about half his health bar in damage.
The Duke of Flies also resembles a powered up version of Hives.
Larger and instead of spawning Large Attack Flies, he spawns Suckers and normal Attack Flies.
Shoots blood in all directions when he coughs, and spawns Moters instead of Attack Flies.
- The name "The Duke of Flies" is a reference to Beelzebub, "The Lord of the Flies", a derogatory name used for a Philistine god and later a demon in Christian mythology.
- This creature is also simply called "The Duke" in the Unholy Edition art booklet. Interestingly, the protective ring of insects he spits out to surround himself with is referred to as the "halo of flies", just like the item Isaac can pick up to protect himself with orbiting flies.
- The Duke of Flies was confirmed to be Edmund McMillen's portrayal of the Pokémon Koffing.
- The Duke of Flies is also a possible reference to The Legend of Zelda's mini-boss Patra, who also has 'flies' circling around him to protect him. These flies more so actually resemble eyeballs with insect wings.
- The Duke of Flies is probably an upgrade of the Swarmer. (speculative)
|Basement||Larry Jr. • Monstro • The Duke of Flies • Gemini • Steven • Famine|
|Cellar||Widow • Pin • The Duke of Flies • Famine • Gurdy Jr. • The Blighted Ovum|
|The Caves||Fistula • Peep • Gurdy • Chub • C.H.A.D. • Pestilence|
|Catacombs||The Husk • The Hollow • The Blighted Ovum • The Carrion Queen • Peep • Pestilence • The Wretched • Gurdy Jr.|
|The Depths||Loki • Monstro II • Gish • War • Mom|
|Necropolis||Mask of Infamy • Daddy Long Legs • The Carrion Queen • The Bloat • Loki • War • The Wretched • Mom|
|The Womb||Scolex • Blastocyst • The Bloat • Death • Conquest • Daddy Long Legs • Triachnid • Teratoma • Mom's Heart • It Lives|
|Utero||Teratoma • The Bloat • Death • Conquest • Daddy Long Legs • Triachnid • Lokii • Mom's Heart • It Lives|
|Sheol||The Fallen • Satan|
|First to fifth and seventh level||The Fallen • Headless Horseman|