Did any of the characters in Beowulf have last names?
The characters in Beowulf did not have last names. Instead, a character is often referred to by the name of his/her father, the clan to which he/she belongs, or the land from which he/she comes. For example, Scyld Scefing (pronounced Shield Sheafing) translates to Scyld, son of Scef. The hero is often referred to as Beowulf, son of Ecgtheow. At other times he is called Beowulf the Geat, associating him with the Geats of Geatland. Other examples include Wiglaf, son of Weohstan; Hygelac the Geat; and Hnaef, king of the Danes.
In all these examples, an element of the oral tradition is seen in the renaming of characters (e.g., Beowulf, son of Ecgtheow). This was a common technique in oral poetry that helped the listener identify the character and kept the poem from becoming monotonous.