Is that right? [Not a question; more of a "that's good to hear". As for the creatures...]
I have. It is rather difficult to avoid hearing them made mention of. [He's encountered a couple of them himself when he's been out - has destroyed each one he's run into - but he'll neglect to mention that. He has been told about them too, after all.
Turns his head slightly in Sherlock's direction, a silent "go on?".]