Short answers, pulled from the story.
Elagabalus was a Roman emperor who ruled from 218 to 222. Born Sextus Varius Avitus Bassianus around 204, he was a Syrian Arab from Emesa and served as high priest of the sun god Elagabal before being declared emperor at age fourteen by the Third Legion Gallica.
His grandmother Julia Maesa orchestrated his rise after the family was exiled to Emesa by the emperor Macrinus. She spread a rumor that Elagabalus was the illegitimate son of the popular emperor Caracalla, winning the support of the Third Legion Gallica at Raphana. Their commander Publius Valerius Comazon declared him emperor at sunrise on the 16th of May 218, and his forces defeated Macrinus at the Battle of Antioch on the 8th of June 218.
Elagabalus promoted the cult of Elagabal, a Syrian sun god represented by a large black conical meteorite called a baetyl. At the end of 220 he elevated Elagabal above Jupiter as the chief deity of the Roman pantheon and built the Elagabalium temple on the Palatine Hill to house the sacred stone. He transferred the most sacred objects of Roman religion, including the fire of Vesta and the Palladium, to this temple.
Scholars regard the three main sources as significantly compromised. Cassius Dio was employed and honored by Elagabalus's successor Severus Alexander and consistently used the name Sardanapalus to disparage the emperor. The Historia Augusta, likely composed in the late fourth century, has been described as largely fictional; its own author acknowledged that stories were invented to discredit Elagabalus and favor Alexander. Numismatic and archaeological evidence has confirmed some religious details in Herodian's account, but modern historians including Martin Icks concluded that Dio was not attempting an accurate portrayal.
On the 13th of March 222, members of the Praetorian Guard attacked Elagabalus and his mother Julia Soaemias at their camp. He tried to escape by hiding in a chest but was found and killed at age eighteen. His body was dragged through Rome and thrown into the Tiber. Following the assassination, the damnatio memoriae was applied: his religious edicts were reversed, the stone of Elagabal was sent back to Emesa, and several statues of him were re-carved with the face of his successor Severus Alexander.
Cassius Dio records five marriages to women, twice to the same wife. His most notorious marriage was to the Vestal Virgin Aquilia Severa, Vesta's high priestess, which violated Roman law that prescribed burial alive for any Vestal who engaged in sexual intercourse. In the last year of his reign he divorced his third wife, Annia Aurelia Faustina, a descendant of Marcus Aurelius, and remarried Aquilia Severa.