We can level after level 20, since I have 3 characters above this level.
Level cap could be 40 ou 30 maybe? I don't know.
And fusion only works between two same characters, like merging Virion with Virion to have a Virion + 1
Shards are for leveling until level 20, crystals for leveling after level 20
The yellow shards are universal between all character classes but they are less efficient than specific shards (If you have 480 red shards and you need 500, you can use 100 additionnal yellow shards. It's not the real...