New Zealand likes to do things differently. The rest of the world knows two legal personalities when it comes to its legal structures. Natural persons and legal entities. The latter are run by natural persons, but independent from them. All legal entities have a built-in limitation of liability, which is the main reason why they were invented in the first place.
New Zealand now got a new form of legal entity or personality, which is the Whanganui river. Its an interesting move, which will mean that the river now has legal standing and is represented through a local iwi group and a government representative. As a legal entity, the river could therefore commence its own proceedings, for instance if applicable environmental laws were breached. Will be interesting to see whether that creates any different results or change anything in the long run, given that quite a few government departments already assume various regulatory functions and have prosecution powers.
But at least it has put New Zealand back on the legal map, at least for some.