When John walks in to find Sherlock calmly sipping tea with a man dressed in what looks like the most extreme S&M gear - complete with the most unsubtle helmet - he thinks he should be more surprised. Sherlock does tend to attract the weirdest clients.
"John Watson, meet Loki of Asgard. He's burdened with glorious purpose," Sherlock intones, and John can't help but snigger. When the man - Loki, what kind of name is Loki? -turns, the noise dies in his throat. It's almost like having a second Sherlock. Loki's eyes appear to see straight into his mind, picking out every secret he's ever had for use at a later date.
"Mock me if you must Sherlock, but I possess that which you most desire." John's not expecting that, the voice smooth and persuasive. The delivery of the sentence strikes John as odd - almost as though it's from another age. "Yes, yes, so you keep telling me." Sherlock rolls his eyes at John. He's surprised Sherlock hasn't kicked this nut job out before now, but John assumes he has his reasons.
"Unite with me against our common foes and I can promise you rewards beyond your wildest imagining," Loki states, and John's view is confirmed. Nutter. He looks at Sherlock, expecting to see him dismiss Loki the way he does his other clients, but Sherlock has sat forward in his seat, apparently intrigued. "So Moriarty has recruited himself a team of superheroes," he mutters contemplatively, "And people assume I have an ego problem."