Which character is described in these lines? lord of the scyldings, this single petition? not to refuse me, defender of warriors, friend-lord of folks, so far have i sought thee, that i may unaided, my earlmen assisting me, this brave-mooded war-band, purify heorot. beowulf grendel hrothgar higelac

Beowulf.

Explanation:

In "Beowulf, An Anglo-Saxon Epic Poem", the author narrates the story of Beowulf, a young Gaetish warrior. He came to the aid of King Hrothgar whose kingdom was terrorized by a monster named Grendel. Beowulf used his epic strength and bravery and slayed the monster, saving the kingdom from further oppression. The above lines are from the lines 56-60 of Chapter VII. It mentioned the time when Hrothgar describes how he had known about Beowulf and his father, Grethel who had been his friend. And now, Beowulf had also came to offer his services to his father's good friend for all the good that he had done for them. 

faithful servants eumaeus and philaetius:

his ragged vest then drawn aside disclosed the sign conspicuous, and the scar exposed: eager they view'd, with joy they stood amazed with tearful eyes o'er all their master gazed:

these servants know ulysses by the scar he got when he was a child - so when he showed them the mark, they immediately knew this is truly their master and they hugged him, finally starting to believe his words.