A Promise Made and A Promise Kept

Kaeya was not an emotional man. He did not let himself get close to anyone, for fear of repeating his mistake a third time. He'd been first abandoned by Khaenri'ah, and then once more by Mondstadt. Both times because he had been too honest, both because he had gotten too close. In the cold clutches of Snezhnaya, Kaeya now had a third chance. Where he could find closure on his previous life, and where he could begin anew.

When he recognizes Lord Tartaglia in Liyue during his escape to Snezhnaya, it is both a blessing and curse. On the one hand, this could be his best chance to learn the language and have an in with the Fatui so he could find some answers on his father's death, disappearing after. On the other, it signals to him that the Tsaritsa has plans for him, confirmed by the Vision now on his hip. He could be walking right into a trap laid out for him, walking into a plan made to ensnare him when he could simply keep moving and avoid all of it. When he ultimately decides to approach Tartaglia, he does so only to get what he needed and to leave without a trace.

Kaeya could never have known that the Harbinger would be his path to salvation.