Claire is a contract Raishou recruited by the second-in-command of the Richior family.
The young master gave her a mission to find a way to marry Hibari Kyouya and sneak into Vongola to steal secrets.
I thought that this was the limit of what a good-for-nothing young man could do, but he didn't expect that one day he would assassinate Hibari Kyouya at Mirofiore's banquet and blame it on the Bovino family. However, no matter whether the assassination was successful or not, she would continue her original plan, which was to marry Hibari Kyouya.
God knows if she would still be alive if the assassination failed. This is simply making things difficult for her as a working class worker.
Purpose: To commemorate the anime I have watched before