Unferth is the hypochondriac human pet of Bob the Cat. He starts A Tail of Two Catsquest, in which he asks you to find his missing pet cat, Bob. After you find him by using an enchanted catspeak amulet, though, Bob reveals that he has fallen in love with a sophanite cat named Neite, which in turn cares a lot about bloodlines when it comes to love. After you help Bob and the Sphinx prove to Neite that he is, in fact, a reincarnation of Robert the Strong, he asks you to do his chores in Unferth's house and take care of him while he comes back home. This includes cutting his fast-grown hair, making him a chocolate cake (the recipe of which can be found in his bookcase), bringing him a bucket of milk and harvesting his potatoes.
However, after finishing Bob's chores, Unferth claims to be ill and asks you to get him a doctor, upon which you must go see the Apothecary. After a humorous dialogue, in which the Apothecary reveals that Unferth is hypochondriac, you decide to disguise yourself as a doctor and make Unferth believe you are giving him medicine that will cure his "illness" (when actually you just give him a vial of water). Since Unferth doesn't recognise you, he drinks the water and comically feels better, claiming that his symptoms are gone. After you talk to him again (without the doctor disguise, of course), you finish the quest and Unferth gives you a reward package Bob left for you while you were gone.
The examine text "nice but dim" could be a reference to the Harry Enfield character Tim "nice but dim" from the popular UK comedy series Harry Enfield and Chums.
Unferth's name might have had influence from Unferth, a thegn of the Danish lord Hroðgar in the poem Beowulf.
During the quest, when you refer to Bob as Unferth's pet cat, he claims that you are wrong and that actually Unferth is Bob's pet human. Furthermore, Neite says that humans commonly mistake cats for their pets, when it is normally the other way around: humans are the pets of the cats. However, since humans without a Catspeak amulet can't understand cats, they prefer to let the humans think they are the owners so they protect the cats and do them favours (carrying them in their arms, for example, so they don't have to walk sometimes).
The Apothecary claims to have visited Unferth to examine his symptoms more times than his mother has had her hair fall out.
When players start A Tail of Two Cats quest, Unferth is bald but as you progress through the quest, his hair grows extremely fast, climaxing after a cutscene, in which Bob remembers that he is a hero, after which Unferth has a long beard and long hair.
During the 2011 Halloween Event, you can read the notice board to find a posting from Bob stating that he has lost Unferth and if you find him, please return him to Burthorpe.