I’m fairly new to this game and this forum so I hope I’m putting this in the right place. I’m finally starting to get a few four-star heroes so here’s my question.
Of the 10 heroes shown, which should I prioritize? Keep in mind Skittleskull and Kiril are costumed (if that makes any difference).
Any advice would be great.
None, you should level 2 rainbow sets of 3* first.
Then Sabina, Sonya, Caedmon.
Come back again after you have the 3* finished for more advice.
Close between kiril and Grimm, in the long term you will make both. Other 4* will also come, so Sabina may be to change as first purple priority.
I already have three 3* rainbow teams fully leveled. So now I would like to focus on my 4* but I’m not sure which ones.
Grimm is a solid 4* hero - his defence down can be a game changer in raids and titans.
Kiril is also useful, but as I would focus on Grimm as blue, maybe focus on Sabina as a healer.
Caedmon was one of my first 4*s and I still use him regularly, a fast sniper with cleanse has many uses.
Kiril, Sabina, and Caedmon would be my choices to focus on for those colors.
You can give Kiril’s costume 1* blue heroes as well when he reaches 3rd ascension, and give the rest of your blue feeders to regular Kiril. Kiril’s costume is really good and useful – he drops defense of the entire enemy team and is very useful for sorcerer trials.
Kiril, Sabina, Caedmon for sure. The green (other than Caed), yellow and red are slow and ones you won’t use after your team grows. Colen is useful and Sonya will help after Kiril is maxed.
Cheers!
Thank you so much for all the responses. I was afraid to even ask for fear of looking silly 
That’s what this forum is here for. Come back for any other questions.
I was going to say Kiril and Caedmon. The third you can make arguments for a few. Nothing wrong with Sabina or Grimm. Grimm is doubling up a color though and more diversity is probably better at this stage in your game.
Red/Purple/Yellow: Colen, Sabina & Hu Tao - those are the only options shown, so work on them. They have their uses, especially Sabina who is a debuffing healer; the other two are good in rush attack, and likely war for you now.
Green: Little John to 3.60, as he’s close to that. Shrubbear after that. He’s a 3* and a very useful one. Caedmon next.
Blue: The hardest choice, as all are good, the same rarity, and not near finished. I’d probably get Sonya to 2.50, since shes 2.26 now, then go to Grimm by a hair over Kiril. While healers are great, defense down is also great, and you have Sabina.
