One of the Deaths is riding on the king. The other Death is wearing a hat that clearly marks him as of lower station in life. It's the same kind of hat that Death is wearing before the nobleman (letter K), the girl (letter S) and on the Holbein dagger (to the left). The same hat appears in the middle of the crowd in All men's bones.
The accompanying text for this letter goes: »Und wie der künig der hut ist / vnd morn wurdt er sterben. Wan keyner vß den kunigen hat gehabt eyn anderen anfang der geburt«.
The first part is from Syrach 10,10: »The physician cutteth off a long disease; and he that is to day a king to morrow shall die«.
The second part is from the Wisdom of Solomon 7,5 and goes: »For there is no king that had any other beginning of birth«.
To the left is a copy designed by Hollar.