Twilight of the Gods
A Thane receives a grant of new lands in a desirable location, at least one housecarl, and a number of thralls. You must answer the Jarl when he calls upon you to defend his lands, his interests, and to go raiding. You may even be called upon to fight as his champion.
A Jarl has multiple thanes who are oathbound to him by oaths of earth, salt and blood. He rules wide lands and answers only to kings.
The Lawkeeper is the loremaster who has memorized all of the laws that bind a people together. He is consulted on any questions of legality, and it is in his presence that the Althing is held each summer.