In my opinion, the "King" is the People of Konoha from the smallest to the biggest to the bravest and the cowardice.
The reason I say his is because, in the recent Manga chapter's Asuma was reminiscing the death of the 3rd while saying to him self "I Finally Understand" If i remember correctly the 3rd was always talking about loving/protecting the people of the village because they are his "Family".
He also says HE, him self is a sacrificial peice, and Shika is a Knight! (Put the game and RL together) you get "protector's" of what? The King.
The King can't be Hokage/is Not, Asuma already mentioned that to Shika when Shika guessed if it was the Hokage. (Asuma used to think it was) so that only leaves these options.
The People Of Konoha
People Important To You
Your Family, Your loved ones (Wife, G/F)
People you Want To Protect
(The last 3 could be put together)
So, it sort of makes sence because... Whats a Hokage without his Villege and His People? Goodbye Village and Its People = -> Goodbye Hokage = -> Goodbye Ninjas (Asuma, Shika, Sacrificial Peice, Knight) -> Nothing.
ˆ-ˆ Of course I could be 100% Wrong!
<3
Could also be.. the "Children" >.>; more like... your.., our children. Kurenai is pregnant with Asuma's baby BAHAH)