Maybe! I do think there's been a plethora of Timelord big-bads already, so I'm hoping it's something new, personally.
*(Spoiler-y ahead)Looking back on it, since 11's timelord-less run, we've only had one season where the big bad wasn't the Master or some other timelord. I think we're due a change of pace.
Maybe another time lord? Rassilon or The Rani
Maybe! I do think there's been a plethora of Timelord big-bads already, so I'm hoping it's something new, personally.
*(Spoiler-y ahead)Looking back on it, since 11's timelord-less run, we've only had one season where the big bad wasn't the Master or some other timelord. I think we're due a change of pace.