the casket of their father
The duke and the king impersonate relatives of Peter Wilks to deceive the townspeople and claim Peter Wilks' inheritance for themselves. They hope to capitalize on the townspeople's sympathy towards the Wilks family to manipulate the situation in their favor and make off with the money.
The duke and king pretended to be the long-lost brothers of the Wilks family and claimed inheritance rights to their fortune. They convinced the townspeople of their identity through deception and manipulation, ultimately swindling the Wilks family out of their money.
In "Adventures of Huckleberry Finn", the King impersonates Peter Wilks, a deceased Englishman, while the Duke impersonates Reverend Harvey Wilks, Peter Wilks's long-lost brother. They attempt to fraudulently claim Peter Wilks's inheritance by deceiving the townspeople.
He gives it to Judge Thatcher for safekeeping so that Pap can't get it
William Wilks
The duke and the king give their part of the inheritance to the girls in "Huckleberry Finn" to try to win their favor and possibly marry them. They see the girls as potential targets for their scams and schemes, so they use the inheritance as a way to ingratiate themselves with the girls and gain access to their wealth.
Huck hides the Wilks family's treasure in the coffin of Peter Wilks before it is buried to keep it safe from the King and the Duke.
The king and duke hid the money in the coffin of Peter Wilks which they stole and filled with lead before burying it. They believed this was a secure hiding spot as no one would suspect a coffin to contain anything other than a body.
Mary Jane
The Wilks Brothers plan to steal the money left in the will.
When Huck goes ashore, he discovers that two con artists, the King and the Duke, have taken over the Wilks family's inheritance by deceiving the townspeople. Huck also learns that the two men plan to sell the Wilks sisters into slavery and further swindle the townspeople.
They were extremely racist, so the duke and kings painted themselves black and they started yelling "n*gger" at them. This shows a clear lack of basic logic, as they witnessed the duke and king putting on the paint, yet called them "n*ggers" as if they had magically transformed races. The verdict? Those girls were balls out crazy. TL;DR Read the book.