User blog comment:Kogath/Monster Hunter XX Discussion/@comment-6050823-20161105095739

Things You May Not Know About Crimson Diablos and Massacre Demon Diablos (Info comes from Hunter's Encyclopedia, The Comic Book Special, MHXX Site, and Famitsu)

Crimson Diablos
 * In a particular small region, it is said that a strange mutation of Diablos was born. This particular Diablos had a crimson-colored shell, was larger, and was far more aggressive than any normal individual.
 * This Diablos was originally only a rumor at the time but, later other regions actually reported Diablos similar to this. These other Diablos looked the same as a normal individual, however, they had one horn and were known to be quite berserk in nature. Due to this berserk nature, these individuals would violently fight threats or rivals until stained with the blood of foes, turning them crimson in color.
 * There was also sightings of one these Crimson Diablos in different regions of the Desert, though this one was said to be bulkier and still roams the endless sands to this day.
 * These Diablos can be best said to be rogue.

Massacre Demon Diablos
 * Massacre Demon Diablos is a special individual of Diablos.
 * Unlike normal Diablos, Massacre Demon Diablos's body is covered in bluish blood and one of its horns have developed strangely due to certain factors.
 * When enraged, the blue blood is said to turn red or crimson in color.
 * Like Diablos, this Deviant is highly aggressive. However, a Massacre Demon Diablos is described to be quite rogue or brutal when it encounters a threat, especially if it is a hunter. When it sees a hunter, Massacre Demon Diablos instinctively sees them as a threat and attacks in a instant. This individual will go out of its ways to make sure that threat doesn't return alive.
 * This is the reason why the Wycademy gave it the additional name, Massacre Demon.