Short answers, pulled from the story.
Commodus served as co-emperor under his father Marcus Aurelius from 177, and as sole emperor from 180 to 192. He was formally recognized as Augustus on the 17th of June 177, though he backdated his reign to November 176.
Commodus was assassinated on the 31st of December 192 by a conspiracy involving his mistress Marcia, his chamberlain Eclectus, and the praetorian prefect Laetus. After a dose of poison caused him to vomit, his wrestling partner Narcissus strangled him in his bath.
Early in 192, Commodus declared himself the new Romulus and ritually re-founded the city, renaming it Colonia Lucia Annia Commodiana. He also renamed every month of the year to correspond with one of his twelve names and retitled the legions, the Senate, the fleet, and the Roman people with variants of his own name.
Commodus identified himself as the reincarnation of Hercules and ordered statues showing him in a lion's hide and carrying a club erected throughout the empire. He had the head of the Colossus of Nero replaced with his own likeness and added an inscription claiming to be "the only left-handed fighter to conquer twelve times one thousand men."
Cleander was a Phrygian freedman who served as chamberlain and favourite to Commodus. He sold Senate seats, army commands, and governorships for personal profit, and in 190 appointed a record twenty-five suffect consuls in a single year. He was executed in 190 after Commodus's mistress Marcia urged it during a public uprising over a grain shortage.
The Senate declared Commodus a public enemy, reversed his renaming of Rome and its institutions, and demolished his statues. He was succeeded by Pertinax, whose reign was brief; Pertinax became the first claimant to be usurped during the Year of the Five Emperors. In 195, the emperor Septimius Severus had Commodus deified to strengthen his own connection to the dynasty of Marcus Aurelius.