Myrddin is a kind and gentle ruler. Fooling people into believing he's merciful, thanks to his young and innocent appearance. All of that vanishes when someone crosses him.

He certainly can be nice, he can be generous, but if someone breaks his rules, execution follows not so swiftly as he throws them in his torturous dungeons for who knows how long.

That rule extends to when someone crosses you, his queen. The actual gentle ruler that wouldn't hurt a fly. He protects you at all costs...