After going to level 50 (max) Valen (blue) special skill level stays on 7. Tried adding 15 additional heroes including blue trainers and non blue as well… help please
Get at least 3 other Valens and some extra 2 stars ice heroes and you will top his special skill. Each Valen adds 25% so if you get 4 you get 100% I did that with my rare heroes team, now they are all complete. Another advice, when you level 3 stars heroes try to use only 1 stars heroes to fuse, that way you will get more chances to get their special skills to level 8.
I had the same issue with Valen (lvl 50, 6/8), I just kept feeding him with spare single blue 1* until finally it worked. Or wait for 4 legendary Valens from your TC20
Or just leave him where he is. The one extra level isn’t going to be the difference between winning or losing an attack