It's gonne be at least the Doctor and Master, since the Master mentioned the Time Lords lying to Us, not You
It will turn out the Master just Now found out about Omega, and was an Omega fanboy at the academy. Doesn’t know the doctor already knew, and burnt Gallifrey down for sacrificing one of its own.
Or regeneration isn’t regeneration, and they simply overwrite a dying time lord with a no dead variant from a parallel universe, thereby destroying the multiverse as they go.