Final answer:
The detail not true about the hero in Beowulf: A Graphic Novel is that Beowulf shows up at King Hrothgar's castle after having killed a dragon. This event occurs later in the traditional Beowulf epic.
Step-by-step explanation:
The student asks which detail about the hero in Beowulf: A Graphic Novel is not true based on class readings. The details provided are:
- Beowulf tears apart the arm of Grendel and hangs its claw high up above near the hallway's towering doors.
- Beowulf once had been in a swimming contest of seven days and seven nights.
- Beowulf tells King Hrothgar to give his armor and sword to his king if he dies fighting Grendel.
- Beowulf shows up at King Hrothgar's castle after having killed a dragon.
Based on our readings and general knowledge of the Beowulf story, detail 'd' is not true. In the traditional Beowulf epic, the dragon is fought by Beowulf towards the end of his life, long after the events involving Grendel and Grendel's mother. Thus, in the context of Beowulf arriving at Hrothgar's castle, he would not have already killed a dragon. On the other hand, details 'a', 'b', and 'c' are generally consistent with the Beowulf narrative, in which he does tear off Grendel's arm, is known for his swimming prowess, and offers his gear to be sent back to his king in the event of his death.