After the rank test has ended, Rex was given a bunch of papers by the staff.
The paper is exactly like what he search on the internet, the time inside the Supernatural territory, family acknowledgment, and death contract.
Rex speed-read all of the papers and finally get the gist of all of it,
The first contract contains a statement of Rex's identity, his current power result from the test before, the amount of time he will spend in the Supernatural territory, and which part of the Supernatural territory will he visit.
All of this will summarize Rex and his purpose in going to the Supernatural territory.
The second contract is the family acknowledgment contract that will have to be signed by a family member, their identity, and their status to the Scavenger.
Mrs. Greene or Robert must sign the contract as proof of approval from family members.
The last contract that Rex needs to sign is the death contract,
