28 март 2021, 00:0028.03.21
It means they're usable in a fusion - take a look at the fusion tab in the summoning portal to see which one. And they do in fact appear on all champions of the same name, if you have several.
FYI, the Rhazin fusion is the most important one, that's a game-changing champion, while Relickeeper is less great but will be required for the progress missions. Broadmaw could be useful as well, with his revives.