Opposition Countering your opponents spells is good, but denying them the mana to play those spells is so much better
Doublers Like the previously mentioned Throne, there are all sorts of ways to double things, whether thats doubling ETB triggers with Panharmonicon effects, counter doubling, token doubling like Doubling Season, or even creature doublers like Reflections of Littjara
Super Sunday Regional Championship Qualifiers in Standard, Pioneer, and Modern
It taps down your opponents biggest blocker, and brings your creature up to par with it in the process
However, King of the Oathbreakerss a good card as a payoff in phasing decks, though itd have been much better at 3 mana rather than 4
Its a solid creature that attacks and blocks well while having incidental value