Is he who watched a series containing mockery of religion, angels, and the Hereafter considered a disbeliever (kafir)? And is he required to utter the Two Testimonies (Shahadatain) and re-perform his obligatory duties such as prayer, fasting, and Hajj?

Allah Almighty commanded turning away from mockery of religion and forbade sitting with mockers, saying: (And when you see those who engage in [blasphemous] discourse about Our verses, then turn away from them) and (So do not sit with them until they engage in another discourse. Indeed, in that case, you would be like them). The resemblance here lies in disobeying Allah's command and committing His sin, not in equating the listener with a disbeliever. Therefore, merely listening to TV series that contain disbelief is not an act of disbelief that expels one from the faith, unless the listener approves, believes, or assents to what is heard. The questioner must offer sincere repentance and increase in good deeds that remove evil deeds.