My King Arthur seems to be stuck at skill level 5. Been feeding him 1 & 2 Star blues like crazy & nothing.
It’s all random, though that is a particularly unlucky case. Try and feed 10 at a time and to maximize the chance to improve. It’s nearly impossible to max out a 5* without getting the special to 8/8, but maybe you could be the first!
Darn, lucky people problems. Have you tried feeding it your other 4 Arthurs for 100% special skill level up chance? Seriously though, congratulations on being able to get that awesome card. The next best thing I can think of is doing a strictly 3* blue diet (TC 15, I think…). It would take you 20 days to get enough blues for a single round of trainings though… Desperate times do call for desperate measures.
1* heroes only are slightly better for increasing the special skill than 1* and 2* heroes (by the time the hero gets to 3.70, for example). It would’ve been much better to do that when he was lower level though, now it will cost more food.
1 at time or 10 at a time makes practically no difference.