mấy cái đó là heirloom, vào bảng item check nó có để điều kiện lấy đó, cứ hạ tướng theo điều kiện thì tăng 7%
A trick to get heirloom items
This is the principle: Whenever you defeat a character with the required requirement to make him drop his heirloom item, and the item did not drop, the percentage chance of getting the item next time is increased by 7%. You can see the current % in the Item screen (the one where you pick your items to use) in the prep menu.
Interim save before you kill the character (with their requirements). If they don't drop the item, reload the interim save again. The game data seems to "save" the fact that you killed them with the requirements, and when you reload the interim save, their drop percent automatically increases by 7%, within that very same battle! Continue doing this and their drop percentages will keep on increasing by 7%, until you get their item to drop.