Office politics between my supervisor's side and manager's side

There are office politics between my supervisor's side and manager's side. The supervisor managed to make manager resign recently and the supervisor start to target manager's side and those political neutral like me. Some actions could be like arrowing us with more work, isolate us and making sarcastic remark. Complaining to HR is useless as most of them are his side and boss is not at work due to his wife just give birth. I not sure what to do as this job is ok to me