I have a rough draft of Sobo and the Fang of Nosferatu started. I just need to polish it a bit and then I will send it to you to get your thoughts.
One issue I am coming up with is Sobo's invulnerability (because of the Fang). He can only be harmed by +5 weapons (+3 in 5e parlance) and has 90% magic resistance (which in 2e means the magic fails completely, not just advantage on saves). Does your party have a means to overcome such strong defenses? Would you like me to water them down a bit? Right now he is immune to most damage and spells.