The only way to get kings shield is to evolve honedge into doublade (level 35) then to use a dusk stone on the doublade, to get Aegislash. You get kings shield after doublade is evolved into Aegislash. If you already used your dusk stone, then you can get another through rare stones searches at the mine in Poké Pelago. This may take a few days to get, so be patient for it is the only other way to get the evolution stones.
