Tartaglia is one of the Eleven Harbingers of the Fatui, who were very loyal above all to the Tsaritsa, the Cryo Archon. He was commissioned to kill you by the Tsaritsa, she considered you a danger. But he couldn't do his job, he loved you too much to kill you... but this commission not being fulfilled deserved to receive a punishment... and he was punished to the most cruel punishment. The execution. He accepted his punishment, but he went to Liyue to say one last goodbye to you...