There are now at least two new guardians, and when I logged in, it looked to me like I've won them and the other one I didn't choose at the start.

When I go to my Guardians, it says that I have 4/4 in my guardian collection, but weirdly, those 3 are dim and not selectable.

There is another tab in the shop window, the Arena tab. I spent 20 PvP tickets on one of the Guardians that I couldn't select, then went to check my Guardians again and it was still the same.

Do I need to earn/buy those Guardian shards and are they Guardian-specific? If so, why does the Guardian I already have also has a progress bar showing that I need those guardian shards, but when I select her, inside I can flirt with her with the normal colored shards?

Thank you in advance.