Orcus

The Orcus is a Pureblood Heartless that is found in Kingdom Hearts 358/2 Days. It is one of the bosses at Halloween Town and Twilight Town.

Kingdom Hearts 358/2 Days
Roxas and Xion separately encounter an Orcus on Day 352 in Halloween Town and fight it, but Axel reveals that the Orcus was not real, and that Xemnas had tried to pit the pair against each other by casting an illusion on them so that they saw each other as the Heartless.

Design
An Orcus is a muscular, humanoid creature with dark purple skin. The tips of its feet are red, and it has small, dark grey wings on its back. It also has an orange wing on each of its elbows. It has a long tail that ends in a silver, circular, pendulum-like blade.

Its small eyes are glowing yellow, and its head features two large, conical, dark purple spikes on either side. It also has two horns with orange tips on its head that connect to each other to form a heart shape. It also carries an ornate, orange sword with a grey cross guard, black edges, and the kanji for "hard shell" printed on its shaft.

The name "Orcus" references the a Roman god of the same name, who was frequently associated with the Underworld and death. Its Japanese name, "Ogre", carries a similar meaning, as the word "ogre" is believed to be derived from the name "Orcus".

Strategy
The Orcus is a rare and powerful breed of Pureblood Heartless that has a very similar fighting style to the smaller, less powerful Invisible. It is swift and will try to stay out of attack range, so the use of magic, particularly the homing Fire spell, is highly recommended. It is important that the player not use any Thunder spells, as they will heal the Orcus. A well-timed aerial combo is another good way to damage this type of Heartless.

The Orcus uses more powerful variants of the Invisible's attacks. It may slash at the player with its swords if at close range, but a carefully timed Block can prevent the damage caused by this tactic. The Orcus is also capable of shooting several downward energy balls that may inflict the Rewound Defense status effect, but this attack can easily be avoided with a simple chain of Dodge Rolls, Air Slides, or even the Glide ability.

The Orcus's last attack is by far its most devastating to one's health; the Orcus will vanish, while its sword flies around the battlefield, dealing damage every time it collides with the player. This will occur several times but can easily be avoided by Dodge Roll or Glide. The Orcus finishes this attack by reappearing and spawning a massive shockwave with a relatively long range and high power.

It is recommended that Glide be used to avoid this attack, but if the player can land a combo finisher when or immediately after the enemy reappears, it will be stunned for several seconds, leaving it vulnerable. Both the energy ball combo and the shockwave tactic will leave the Orcus vulnerable to attack to some degree, so long as the player dodges the combo first and then moves in swiftly with a quick aerial combo.