Ogre

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
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 has four main attacks. If you know the signs you can see them coming. The easiest way to defeat him (but not the best) is to strike right after he either flies toward you slowly and then strikes and to hit him after he fires out the purple balls. The hardest attack to dodge is when he sends his sword flying around the area, homed onto you. Then after the sword passes you a few times the Orcus will appear (you know when there is a big purple ring in the sky) and create a shockwave. The best way to try and dodge his flying sword is to roll out of the way. If you time it just right it should work. But if you do get hit make sure to heal yourself quickly. Another way to attack him is to perform an aerial combo against him when he comes out to use a shockwave attack. Just jump up and perform a combo. If you time it right the Orcus will be stunned and you'll be free to attack him without any counters or dodges, but make sure you get out of there quickly when he recovers! Another note, don't use Thunder spells against him because they heal him.