Duke
From AmtWiki
The third highest title in the Amtgard Order of Precedence, above Count but below Archduke. Generally awarded for a single term as Kingdom-level Monarch. The proper form of address is "Your Grace", or "His Grace James, Duke of York". If appropriate, "Sir" may be added after "Grace". It is also appropriate to just refer to a noble by their title and estate, like "the Duke of York"
'Female Variants'
'Male'