Malphas is described in the Ars Goetia as a Prince of Hell, commanding forty legions of demons. He appears as a crow, but if requested will instead resemble a man with a hoarse voice. Malphas specializes in the construction of houses and towers, knowledge of enemies' thoughts, and bestowing familiars. He will attempt to deceive his conjurer, however, and must be treated carefully.
In Castlevania, Malphas first appeared in Castlevania: Symphony of the Night, and was called "Karasuman" (Crow man) in the American version, likely to avoid religious controversy (note that Biphron, Ukoback, and Legion also had different names, although Beelzebub remained unchanged). He is the boss of the Clock Tower, and fights in the same room where Richter faced Shaft's Ghost in Castlevania Dracula X: Rondo of Blood. Several Malphases appear as regular enemies later on in Death Wing's Lair.
Malphas fights in three ways. After unfolding his wings on the ground, he will draw the essences of many demon crows inside him, and unleash them in a massive wave. His second attack is to fly into the air and fire spreading, directed feathers. Malphas can also fire energy spheres, although this attack is not seen as often. However, Malphas is slow to attack, and easy to knock off balance, and thus he is one of the easier bosses of the game.
In Castlevania: Harmony of Dissonance, there is a remarkably similar enemy called the Feather Demon. It does not use Malphas's raven attack, but it is very obviously the same type of creature, only redone for the sake of the Gameboy Advance's lower technology.
Malphas makes a cameo in Castlevania: Aria of Sorrow, as he is his soul that gives you the double jump. However, Malphas does not actually appear in the game.
Malphas makes a proper return as a boss in Castlevania: Dawn of Sorrow in the chapel, in which he guards the double jump ability.
Several Malphases appear as late-game ordinary enemies in Castlevania: Portrait of Ruin.
Castlevania: Symphony of the Night
Castlevania: Harmony of Dissonance
Castlevania: Dawn of Sorrow
Oddly enough, Malphas is the only boss aside from Menace that doesn't apear in Boss Rush Mode.