Ha ha. Actually, the mask is kind of a religious thing. Akiva is from House Galbraith, who are kind of like the papal state of the empire and they all wear masks made of bone and pewter as a kind of weird ceremonial thing (they're actually never seen without them on!).
And yes, Akiva is actually a nice enough dude, despite the creepy look. His son, Ilan, will play a big role in the story and will have quite the history with Linus when all is said and done. :p