The OP is speculating about a male balance to the feminine Sidhe Court, using the Kings as equivalents to the Queens, the Knights as equivalents to the Ladies, and an unknown male individual/pair as equivalents to the Mothers.
Oh it's much deeper than that, properly, he'd be their combined equal. But as the hunter of shadows it can go a bit deeper. Can't peg down which creation mythos it was anymore but the idea of the eternal shadow being endlessly divided and then projecting those divisions into the light holds some merit when you consider time=oblivion=nonexistence. The factiod 'everything stops' when outsiders get in also, death only being a thing in a existence that surpasses wuji, one state into yin-yang. the one state accures when the hunter has recollected all the shadows specifically. So he's technically as powerful as everything in existence combined... op enough I think.
LoST being the Mothers' equal seems like a downgrade for him, but aside from that, it doesn't really meet the purpose of the speculation.
*boggles a moment at limiting any such speculation to a narrow purpose*
Anyway, the idea of a pair to balance them is where the error accures imo. Combine the 'matter anti-matter' woj with the fact Kali is a destroyer and the combined mask of The queens looks a lot like her.... That they are specifically straddling the balance and are separated in such opposition to keep said whole from manifesting in reality and it all starts to become much more palatable.
The balance is pretty easy, 5, it's 5 broken down throughout every pantheon or court we've seen, they just break down into smaller aspects of reality. So you have to take that into consideration on if it's a split of an existing archetype or another version holding aspects. The Kings tend to not deal with splitting imo, simply being opposite shadows of each other without having the same aspect.