Oscar Fredrik Dronjak (born January 20, 1972) is the rhythm guitarist and founder of the Power Metal band Hammerfall. Prior to the success of Hammerfall, he also played and released albums with the death metal acts Ceremonial Oath and Crystal Age. Dronjak was born in the Swedish town of Mölndal to a Serbian father and a Swedish mother. His first instrument was the accordion; he then played trombone for a few years until, at the age of fourteen, he settled on guitar. Soon after, he started his first band, called the The Hippie Killers.