When writing a fantasy novel, you can borrow the power system/upgrade system of other people's works, but you have to adapt and use it appropriately. When borrowing the power system of other people's works, one had to consider the copyright issue and obtain the author's authorization. In addition, he also needed to adapt the original work to match his own work. The methods of adaptation could include deleting, adding, adjusting, and so on. When borrowing the upgrade system of other people's works, one had to consider the style and setting of their own works. If the style and setting of the work were different from the original, the upgrade system would need to be adjusted to suit the style and setting. When using the power system and upgrade system of other people's works, you need to be careful not to copy too much or treat it as your own original work. It should be regarded as a source of inspiration and reference for appropriate adaptation and application. When writing a fantasy novel, you can borrow the power system and upgrade system of other people's works, but you have to adapt and apply it appropriately to ensure that your work is legal, original, and interesting.