Duel points are awarded only after the union has won the duel, and the members of the union have taken the reward chest.

The union member who takes the chest receives the number of points shown above the reward. The points of all participants who took the chests are summed up and go toward the overall standings of the union.

The higher the prize level, the more points you’ll get.
The losing union also receives a small number of points.

Look at the chest: If it is transparent, it means that you have not gained enough points and cannot yet receive it if you win.

Continue completing missions! Once you get enough points, the chest will become fully colored, and you'll be able to claim it if you are victorious.