These creatures come in many forms, and many are shapeshifters. In the TV series, the AMP classifies them into three categories:
Category III: low-level creatures that are little more than animals. These often resemble snakes or mantas or other animals.
Category II: beings of slightly less than human intelligence and modest magical powers. There is great variation in their appearance. These usually appear capable of summoning various category III Lucifer Hawks that act as their "minions".
Category I: typically somewhat humanoid with magical powers equal to those of even the most power human mages. At least as intelligent as humans, this category is very eloquent and prone to various mind games as shown in the anime.
Category IV: Human-Lucifer Hawk hybrids. Not a real category in the AMP's classification, as it only appears in an illusion crafted by Ganossa Maximillian to trap Katsumi Liqueur. She and the Cheyenne sisters are the only known members of this class.
The more powerful Lucifer Hawks are capable of assuming human form and large collections of lower level ones can take on the form of large objects, such as the AMP's Simurgh command vehicle. Lucifer Hawks can meld with physical objects such as buildings or computers. The more powerful ones have great regenerative powers, but ordinary handguns can kill the lesser ones.
Lucifer Hawks are capable of breeding with humans, as evidenced by the Cheyenne sisters. According to Grospoliner, Katsumi (and possibly other mages) have distant blood ties to the Lucifer Hawk from liaisons many generations ago.
