The King of Knights and the Elden Lord are two people who are quite similar, yet also quite different, they are people who will fight to their core, willingly die for their master and their morals. Though Artoria is more graceful and noble, Mal is a nobody and casual, despite that they respect each other and have each other's backs. As much as they might bicker to each other, it won't stain their relationship and they won't break that friendship either.