Tbh, I don’t really like how easily MC become king…
Mainly because….
This acknowledgement, is no different then “self proclaimed” one….
He should at least perform coronation ceremony and approved by multiple kingdoms or nations, at least those who shared borders….
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Another method, is by conquering other kingdom, pretty much automatically grant the victor, kingdomhood…
While coronation ceremony would be like an afterthought, no weak kingdoms, would object without reason…
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The 3rd method is actually through political marriage with another royalty, that then acknowledge the kingdom hood…