The Great Deputy King, in full Maha Uparaja Anaudrapa Ainshe Min, incorrectly interpreted as Crown Prince by Europeans, and addressed as His Royal Highness, was the single highest rank among the Min-nyi Min-tha, i.e. princes of the royal blood.
However, the position was not reserved for the highest birth rank (if there is one, Shwe Kodaw-gyi Awratha, i.e. eldest son of the sovereign, by his chief Queen), nor did it carry a plausible promise of succession, which was usually only settled in an ultimate power struggle.