Merlin comes to bed that night silent and near tears. He won't tell Arthur why, but his grief is strange enough to pull Arthur out of his own stupor of mourning. Merlin never particularly liked Uther. Arthur knew and understood this. Sometimes he didn't like Uther. But Merlin won't tell him what he's upset about. So when Arthur can bear to talk to people again, can actually look at something other than his father's corpse, he takes Merlin to bed and he holds him. Just holds him and strokes a hand through his hair, for hours. Merlin never makes a sound, but Arthur feels the tears that hit his chest as Merlin rests his head on it. He holds him all through the night, trembling with helplessness, first his father's death and then his husband's grief.
"Tell me," he wants to say.
"Who hurt you," he wants to ask, so he can hurt them back. Nobody hurts what is his.
But he doesn't say that, and it isn't until years later when he knows the truth that he realizes… he didn't need to ask.
Deep in his soul, he already knew the answer.