Who owns Mjolnir? The fact there is a new Goddess of Thunder in Marvel comics causes pause over property rights. Let’s begin our journey into legal mystery on how worthiness is a condition for property ownership.
Thor’s Hammer technically should be personal property that an individual would own. As the Hammer was constructed by the dwarf Eitri in the comics (Sindri and Brokkr in Norse Mythology), then given to Odin by Eitri, and then given to Thor Odinson by Odin, Mjolnir should be the personal property of Thor Odinson as a gift from his father (Wikipedia has a summary of the Hammer’s creation).
However, as fast as you can say Beta Ray Bill, Mjolnir is inscribed with, “Whosoever holds this hammer, if he be worthy, shall possess the power of Thor.” As such, Mjolnir requires someone to be “worthy” in order to even lift the Hammer.
The requirement of “worthiness,” as judged by a sentient super weapon, creates a situation where the owner of the property could not use the property (Mjolnir), if the property deemed its owner “unworthy.” As such, Thor Odinson’s ownership in Mjolnir is conditional and can be revoked by the Hammer itself based on the user’s worthiness (Or in the case of Beta Ray Bill, someone who is worthy can have a competing ownership interest in Mjolnir).
There are no epic legends of lawyers in Norse Mythology, but this is legally odd. Normally a revocable transfer of property would allow the transferor to recover the property. In the case of Mjolnir, the Hammer was not transferred back to Odin (who the Hammer also deemed unworthy), but (apparently a human) woman who has yet to be identified. The fact the Hammer effectively selected its own new owner is outside the norms of existing property ownership laws.
In Thor #4, Thor Odinson confronted the new Thor to recover Mjolnir. There is a strong argument that Odinson had a valid claim to recover the Hammer. After all, the Hammer is personal chattel that Odinson had owned for centuries. However, as Mjolnir deemed Odinson unworthy after Nick Fury whispered something damning to Odinson in a fight above the Moon, the Hammer summarily revoked Odinson’s ownership interest. As such, ownership transferred to the yet to be identified new Thor based solely on worthiness (and her ability to travel to the Moon and without the need to wear a spacesuit).
What is legally unknown, is why Thor Odinson is no longer worthy to wear a shirt. The Tetsuo Shima look is a bold choice, but not proper courtroom attire.