Galaxia Card Reference

Galaxy Card reference, also known as the dropped galaxy cards that you can obtain through the galaxy dungeon reward, if you're lucky, persist of a skill card, that will grant you +1 that skill level or +2, depending on that card. These cards can be fused into A ring, creating that skill of yours being +2 levels higher, (Max skill lv 10) So if you already upgraded that skill to level 10 using monster cards it won't be possible to upgrade it any further.