The Duke Rank has the following perks:

All Count & Noble permission perks plus:

•  4 jobs
• Can disguise as Chicken, Cow, Donkey, Mule, Horse, Mooshroom, Polar Bear, Rabbit, Sheep, Squid, Villager, and wolf
• 10 sethome slots
• Access to /fly
• Access to /speed
• Access to /back
• Gives 75$ in game money
• Access to /kit duke (1 tool crate key, 1 perk crate key, and one june crate key.)
• Exempt from AFK kick when server is full.