15. Justice systems were (almost) like ours
The Norse had an oral culture that helped establish both law and government without so much as having a written text. All free men gathered in their communities to make laws and decided cases in meetings called a Ting. Each community had its own Ting. Like our legal systems, there was a plaintiff and defendant, and a jury.
They were most likely made up of a local, powerful family, or sometimes multiple families. Malefactors who are tried and found guilty are either fined, declared semi-outlaw, or fully outlawed. To be an outlaw was complete banishment; his property would be confiscated and he would receive no help from the community.