The tone of this passage from the Anglo-Saxon epic poem Beowulf is clearly mournful. Hrothgar and his people have been harassed by the marauder Grendel, a murdering monster who will eventually kill Hrothgar's people for twelve long years. This passage, however, comes after the first of Grendel's ravages.

For the dead. Hrothgar, their lord, sat joyless
In Heorot, a mighty prince mourning
The fate of his lost friends and companions,
Knowing by its tracks that some demon had torn
His followers apart. He wept, fearing
The beginning might not be the end. And that night....

Note the setting of this passage. King Hrothgar is sitting on his throne, deeply mourning the loss of his "friends and companions." The mourning prince is "joyless" as he remembers those who have been brutally murdered by Grendel. He has lost not one friend but many; and, even worse, they were killed in a most gruesome and awful way. The tracks leading from the terrible scene indicate a monster which is another reason to fear the future and mourn these losses.

Hrothgar's mourning is complete when he begins to weep, both for his own loss and the loss of his people and with the fear that this is just the beginning--that there will be more loss of life. 

The details and the language both convey Hrothgar as a man in deep mourning for the loss of life and for the future.