In Earth’s late Saxon and Norse cultures, especially post Christianisation, there were plenty of codified laws and a system known as Wergild. Wergild is derived from OE were for man (as in werewolf) and geld for payment (as in the Danegeld) and is a system of blood money, with a variety of payments due the injured party for a variety of crimes. For instance killing a slave will cost you 60 shillings, a Ceorl 200 shillings, a Landless Thegn 600 shillings, and Thegn 1,200 shillings. Which is all very interesting, but for Redwald I’ve gone with the older Blood feud, might is right, form of (in)justice as it’s a little more chaotic and offers more potential for trouble.
It’s very basic. The lord, whether he is Thegn, Ealdorman, or King keeps the peace. His word is law and he backs that law up with his sword. If you kill, injure, or insult someone they or their family will try to seek vengeance in the old fashioned and direct manner.
It’s not uncommon for a blood feud to run for generations, or escalate in to a very nasty conflict splitting entire communities. Of course trying to seek vengeance is the key here. If you’re a Ceorl a mere farmer, you’re unlikely to have much luck seeking vengeance against a Thegn or Ealdorman. Usually though it’s the local lord who ultimately puts an end to a blood feud. Either simply by warning all involved the bloodshed must end, or by taking sides and ending it by eliminating one of the factions. Not pretty, not fair, but hopefully lots of adventure fodder.