Hvitserk (Hvitsärk) "White-Shirt" was one of the sons of the legendary 9th-century Norsemen Ragnar Lodbrok and his wife Kraka. He is attested to by the Tale of Ragnar's Sons (Ragnarssona þáttr). He is not mentioned in any source which also mention Halfdan Ragnarsson, one of the leaders of the Great Heathen Army which invaded the Kingdom of East Anglia in 865. Consequently some scholars have suggested that they are the same individual. 
After having avenged his father together with his brothers, he went pillaging in Gardarike (Garðaríki). He was, however, opposed by such a large foe that he could not win. When asked about how he wished to die, he decided to be burnt alive.