Argosax

Argosax the Chaos, also known as the Despair Embodied, is a powerful demonic king and one of the main villains of Devil May Cry 2.

Life before Devil May Cry 2
Argosax, at one point, ruled the demon world and was worshipped by the people of Dumary Island, where Devil May Cry 2 takes place. Eventually they recognized him as an evil demon and he was defeated by the Dark Knight Sparda and the Vie di Marli, a group of demon hunters that use demon powers.

Devil May Cry 2
A business man named Arius, who had knowledege in demonic magic, sought to claim Argosax's power. He then began searching for the four Arcanas, mystical items which were used to seal Argosax away. Dante manages to interfere with Arius's ritual by replacing the Arcana Medagalia with a coin of his own. However the gateway to the demon world is still partially opened and part of Argosax's power flows into Arius. Dante and Lucia debated who should go through the portal since because it is unstable, it is unlikely that anyone who enters it will be able to return. Dante left it to a coin toss, which he won because of his two sided coin, and entered the demon world. Upon arriving, he was confronted by Argosax in his first form, Argosax the Chaos, an enormous fleshy blob with parts from the bosses in Devil May Cry and Devil May Cry 2. Upon defeating this form, a large egg sprouted from the blob and out of it came Argosax's true form, the Despair Embodied, a androgynous, horned, angelic being composed of fire. During the fight, Argosax changed sexes and weapons, as a female, it wielded a fiery whip and as a male, it wielded a flaming sword. Despite his great power, Dante defeated the demon lord.

Powers
In his Chaos form, he can use the attacks of the bossses that comprise him, such as mouth blasts from the head of Nefasturris and lightning waves from the wing of Griffon. After entering his Despair Emobdied form, he could teleport around the battlefield, fly, and rain down waves of fiery feathers.

Trivia

 * The four Arcanas are a coin, a cup, a sword, and a staff, which are a reference to the European suits of Tarot cards, which were also known as Arcana.