The user/user is a "node type" to "node type" thing: it can be user/item f.ex. The marc/marcus is related to those so for user/item it could be marc/sword f.ex

The user/user is a "node type" to "node type" thing: it can be user/item f.ex. The marc/marcus is related to those so for user/item it could be marc/sword f.ex. The reason it's that way is that how it needs to be stored on disk. The detail data (what the relation has as meta data is subordined to the relationship of nodes user/user), you can put anything that marc/marcus have in common in that JSON file. (I just added that we used to be colleagues) Even if it feels awkward when you are used to wasteful structures once you know this is the least complex solution you will be thankful, specially in the long run since you wont have to learn anything else ever again.