Short answers, pulled from the story.
Otho ruled for 91 days, from the 15th of January to the 16th of April 69 AD. He was the second emperor of the Year of the Four Emperors. His reign was the shortest in Roman history until Pertinax, whose 87-day reign came in 193.
Otho chose suicide rather than continue a civil war he believed would cause more Roman bloodshed. He told those around him that it was far more just to perish one for all than many for one. He died on the 16th of April 69 AD, one day after the battle, stabbing himself with a dagger he had concealed under his pillow.
Otho married Poppaea Sabina, but Nero, who desired her, forced Otho to divorce her so he could take her himself. Nero then exiled Otho to Lusitania as its governor in 58 or 59. Otho never forgave Nero for the marriage.
The Battle of Bedriacum took place on the 14th of April 69 AD, approximately 35 kilometers from Cremona. Otho's forces, including the Praetorian Guard, suffered a decisive defeat against the army of Vitellius. The two sides together sustained around 40,000 casualties.
Otho was a member of a noble Etruscan family and a close friend and courtier of the emperor Nero. After Nero took his wife Poppaea Sabina, Otho was sent to govern the province of Lusitania around 58-59 AD. He later allied with Galba during the revolts of 68 and accompanied him to Rome.
Otho appears as a character in Monteverdi's 1643 opera L'incoronazione di Poppea, Handel's 1709 Agrippina, and Vivaldi's 1713 Ottone in villa. On film, he features in multiple recordings of the Monteverdi opera and in the 2013 Polish film Imperator, shot entirely in Latin, where he was portrayed by Robert Wrzosek.