"But one night after continued his slaughter..."
See in text (III)
The loss of so many of his guard humiliates and saddens King Hrothgar, who gets no respite from the first attack because Grendel remorselessly strikes again the very next night. Since Hrothgar and his people have no time to grieve, Grendel's relentless attacks create an atmosphere of despair and helplessness around Hrothgar's Hall. The tension and anxiety build as the audience awaits the arrival of a champion.
"and forced from their slumbers
Thirty of thanemen..."
See in text (III)
In Grendel's first attack on Heorot, we are witness to the power and size of this creature. The fact that he is able to take thirty thanemen, or soldiers sworn to the service of their king, from the hall and take them back to his lair shows us that this evil creature has strength beyond normal human capacities. Details like this help the poet create an atmosphere of dread and terror.
See in text (IV)
At this point in the story, the poet introduces the hero of our tale but has yet to state his name. By not naming the hero immediately, the poet starts to build a reputation for him, alluding to his great deeds in an effort to make hero's self-introduction more powerful for the audience. This creates a sense of anticipation and suspense as the audience wonders who this hero is.
"Art thou that Beowulf with Breca did struggle,
On the wide sea-currents at swimming contended..."
See in text (IX)
Unferth challenges Beowulf with a story he heard about a swimming contest between Beowulf and Breca. He accuses Beowulf of competing and swimming into the deep main (the ocean) simply for vanity rather than honorable reasons. This challenge serves as a direct challenge to Beowulf’s claims and provides tension by introducing a minor antagonist.
"falsehood and treachery
The Folk-Scyldings now nowise did practise...."
See in text (XVI)
The poet foreshadows dynastic problems that are yet to come for Hrothgar's Danes. The mention of Hrothulf, Hrothgar's nephew, may support the belief of some scholars that the foreshadowed treachery involves both Unferth and Hrothulf against Hrothgar. This lends the poem an ominous mood that contrasts with the feasting earlier mentioned.
"Doomed unto death..."
See in text (XIX)
The poet uses the concept of fate to foreshadow the death of one of the warriors at the feast. For those living during Beowulf's time, when a man is fated to die, he will die, and there is no action the man can take that will alter his fate; this is why the man is “doomed unto death,” giving the end of this section an ominous tone.
"His life on the shore, ere in he will venture
To cover his head...."
See in text (XXI)
The description of the moor, or bog, details the surroundings as exactly the opposite of the homes of humans—cold, dark, and mysterious. The lake in particular adds to this unknown and treacherous environment, particularly its indiscernible depth of the lake and that a strong deer would rather be killed than enter the mere. The poet's description sets the mood for Beowulf's encounter with Grendel's mother by establishing that he will have to enter her realm.