Tartaglia, also known as Childe, is my favorite Harbinger because I love his personality and caring nature for his family. Although he follows the orders of Her Majesty, he has a soft side to him where he cares for his family and will do anything to ensure they are safe. For instance, there was a quest where his brother Teucer came to meet him in Liyue, and he trusted the Traveler to take care of him. Not only that, when Teucer was in trouble, Childe used his Delusion to eliminate existing threats at the cost of his own health and ended up in a fragile state. Though it's undeniable that his actions risked the lives of the people of Liyue and the whole city was on the verge of destruction, I cannot say he's purely evil. Surely, there must be some reasons he had to act that way, but his nature towards his family is also you cannot ignore. There have been various instances, like his introduction to the game, where he saves the Traveler from the Milileth and helps him escape. So, ultimately it's not yet clear what he has in his mind, but on numerous occasions, you will learn about Childe's good side. I would say only the time will answer our questions in the future and how the events will unfold.