This is an absolutely beautiful sketch of Ezio. The shading is superb and well-measured, the hood shape is extremely accurate and his expression could not be more fitting.
The only criticism I have is that his nose appears to be facing towards the right, whereas his head is facing towards the left (this is a very slight fault though and is barely noticeable). In addition to this, the facial hair could perhaps be a little more defined.
That aside, magnificent work!