[He can't help but laugh, smiling brightly at Grell, despite his words indicating he should affect the 'grim countenance' Stevenson said he so desired of himself...]

Even so, perhaps you yourself do not, yet I have never been able to let these formalities go for long at all...

[A short pause.]

But, if you mean to say you would rather be addressed by your given name, I would like that.

[It's an honest smile, too innocent and excited. But maybe not so strange to see, considering his apparent age, hardly an adult (if at all), a look much more appropriate to this personality than the other.]