Orcus

The Orcus, also translated as "Ogre" in Kingdom Hearts Union χ and Kingdom Hearts Dark Road, is a Pureblood Heartless that was introduced in Kingdom Hearts 358/2 Days. It is one of the bosses at Halloween Town and Twilight Town.

Kingdom Hearts 358/2 Days
On Day 352, Roxas and Xion are sent on separate missions to Halloween Town, where they encounter and battle an Orcus. Axel appears and reveals the Heartless to be nothing but an illusion; Xemnas had attempted to pit Roxas and Xion against one another through this mission. To give the friends an incentive to fight, he had used the illusion that produced the Orcus to make them appear as Heartless in each other's eyes.

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 Core" (硬核) are written on the hilt of its blade.

The name "Orcus" references the Roman god, 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 not to 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 Roxas 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 Roxas. 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 Roxas 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 Roxas dodges the combo first and then moves in swiftly with a quick aerial combo.