There are no rules for any Val family beyond the “Big 13” and the val’Holryn. As such, you cannot play them. We’ve been promised rules for the val’Sungha for over a year, but between family emergencies, real life, WitchHunter and Rotted Capes, PCI hasn’t gotten around to releasing additional families.
That said, the val’Sosi are probably so rare they would not be allowed except possibly as a reward to specific players, similar to how the old Invisible Kings and Queens were allowed to play val’Cessari characters.
