He attacks similarly to the original Yellow Devil, and his weakness (the eye) can appear on different parts of his body, which can throw the player off-guard. After he loses a lot of energy, he will turn into Dr. Wily's Wily Machine from Mega Man 6 and attack the player faster, making it harder to dodge his attacks. During the short duration of this form, the eye will periodically appear at the dome of the skull. His background music is a remix of the fortress boss music from the first Mega Man game, and a warped "W" appears in the background.
- The Shadow Devil is weak to the Tri-Thunder weapon, but can only be damaged by it while his bright-red eye is exposed. This is a direct throwback to the original Yellow Devil's weakness to Elec Man's Thunder Beam (which itself is nearly identical to the Tri-Thunder).
- If possible, when the Devil melts and breaks apart, try avoiding his blobs as they travel across screen. If the Devil's eye shows up, try to fire a fully charged shot on it.
- Also, when the Devil migrates to the other side of the screen, he leaves behind a green outline of himself where it used to be. X and Zero will get damaged heavily if they touch the center of the outline. The outline disappears when the Shadow Devil has completely re-formed on the other side.
- Yellow Devil
- Yellow Devil MK-II
- New Yellow Devil
- Green Devil
- Grey Devil
- Dark Moon
- "Twin Devil"
- Block Devil
- Rainbow Devil
- Lava Demon
- Deviled Egg
- Dark Devil
- Early in its development, Shadow Devil was originally called "Metal Devil" and was silver. His color was later changed to black to better emphasize the lights around his eye.
- The Shadow Devil is considered to be the toughest Devil robot, as well as one of the toughest bosses in Mega Man history, as its attacks can heavily drain the health gauge and may also lead to an instant death if the player is unprepared.
- The Shadow Devil's stage is very similar to Quick Man's stage from Mega Man 2.