He has pale white-blue skin, wears a white band that covers his eyes, has a large stitch on his chest, and rides on a white horse.
Conquest's behavior is somewhat similar to War. He shoots 4 fast purple homing shots in the cardinal directions. Sometimes Conquest teleports off-screen and random locations are bombarded with beams of white light, similar to the Crack The Sky item. Conquest also charges off-screen and summons several clones of himself that charge alongside him.
The following should be considered when battling Conquest:
All damage done to the clones during his multi-charge attack will affect Conquest as well.
The further away you are, the more time you have to dodge his homing bullets.
During his beam attack, try to not make sudden movements to reduce the chance of running into beams.
If Isaac has Flight and there are rocks to fly over, the beams will not hit Isaac, as they cannot go above rocks.
The beams will not hover over any areas where doors can potentially appear.
Eternal Conquest's charge-off-screen attack spawns Gazing Globins as he summoning clones, though most of them are soon killed during his charge. The "Crack The Sky" attack has more white beams.
Like the A Pony item, the White Pony can be re-rolled with The Dice if it is picked up, replaced with The Dice again, and re-rolled.
When using The Gamekid on Conquest while he is charging, all of the copies will flee and only the original Conquest can be damaged.
When Conquest flies off the screen, he cannot return if there are too many objects on screen. For example, Crack the Sky and Anarchist Cookbook will delay his return.
It is possible to unlock Conquest before The Harbingers are unlocked. However, this will have no real effect, since Mom still has to be defeated for The Womb to be unlocked, which also unlocks the Harbingers.
His beams can hit himself (for 1/10 damage of the Crack The Sky beams).
Conquest is the first of the four horsemen of the apocalypse as depicted in the Bible (Rev. 6:2), but is often erroneously replaced with Pestilence in popular culture.
"A Forgotten Horseman" might be a reference to Edmund using the biblical incorrect Horseman in the original game or the absence of Conquest in a large part of popular media.
Conquest seems to have a stitched Y pattern on his chest like The Duke of Flies (Indicated by the boss art).
On rare occasions, War can be replaced by Conquest, despite the versus screen telling that War is the boss the player is about to fight. The battle is a standard fight with Conquest, but a Cube Of Meat is dropped instead of the White Pony.
Interestingly, Conquest is shown as War on Isaac's Last Will.
It is possible for Conquest to kill himself while shooting down beams of light. A sound similar to that of a normal monster dying will be heard, and a single splat of blood will fall to the ground (almost like the beam hits some kind of dummy unit). Then the game proceeds as though you had defeated Conquest as usual.
When using The Gamekid, some copies of Conquest appear at the sides of the walls, and can be run into, but no damage will be dealt. They disappear after the duration of The Gamekid finishes.
Conquest can spawn without being unlocked. In the source-code, there is no check for "required" unlock.
Conquest can also get stuck in a wall when using his charge ability. This leaves him invulnerable and impossible to defeat normally.
When using The Sun card upon entering the room, he may disappear and be stuck in the center of the room to be killed.