0 voters
I don’t have 5* ice hero so I have to deal with this fellas. Currently I’m using Boril and I’m really happy with his contribution. I’m considering Sonya as a substitute because of her fast mana and her special. Thx in advance 
I use them all. You could put all five on a team together and do pretty well. Seeing the rest of your roster would be helpful.
Also, is this for attack or defense?
It’s for attack. Rest of the team is Boldtusk, Gadeirus (also considering to replace him with Caedmon), WuKong and Seshat.
It sounds like you have some depth. I would recommend considering a stack instead of raiding rainbow. For instance, if you’re facing a blue tank, take Gadeirus and Caedmon and leave Boldtusk out.
Also consider varying your team composition depending on who you’re facing. For instance, Caedmon, Sonya, and Seshat all dispel. Taking all three may be unnecessary.
Finally, I’ll vote for Grimm, since you don’t have a defense debuff hero in your lineup. But I also use Triton a lot, and he helps with partial healers like Gadeirus, Boldtusk, or Kiril.
Kiril will last you the longest as he can only be somewhat replaced with Ariel. Grimm is also a key hero for titans till you get a 5* blue with def debuff.
This is speaking long-term and it looks like you are maybe looking for more immediate use. Since you have Seshat on the team, I would put Grimm as priority.
In general, if you play the game for a while and move up to 5*s , you will see less use of some of the 4s. Many will only be used in tournaments. My ranking would be.
Thanks fellas. Sorry to hear about Boril. I find him pretty useful. Lots and lots 5* star snipers and hard hitters were offed by him alone, not to mention bosses in season 2. I would never get to province 20 without him I think. I had Kiril before but Boldtusk took his place as a partial healer.
Boril is not a bad hero at all and is extremely useful at lower levels. Its just that he drops off later in the game. Cyprian was my first maxed 4* and I used him for a long time.