According to the official blog, new master and butler of Kuroshitsuji II
was announced at a live event "Kuroshitsuji ~Sono Shitsuji, Kyoso~ Akai Valentine". Kuroshitsuji II will be aired from this July.
New characters and cast
Claude Faustus (Bulter): Sakurai Takahiro
Alois Trancy (Master): Mizuki Nana
A rough sketch of the two characters
It's unknown that Sebastian and Ciel will appear in the second season.
Source: Kuroshitsuji official blog