I have been short of capes and finally got fourth one.
Who wears it best: Sonya, Kiril, Boril, Triton? All are level 3/60… (very long time very short of capes)
I have maxed BT, Caedmon and Grimm who is my only maxed blue 4*. (I also have Ulmer, Gato,Valen, Gunnar, did I told you I was short of capes).
My vote is for Kiril. Very useful in wars and… everywhere else.
I’d go with boril! You already have a debuff with ceadmon! If not him, sonya, sorry, kiril! All the way, just re read who you have!
They’re all pretty good with Kiril probably being the most versatile and useful for the longest.
Boril is probably the least versatile unless you particularly need a tank or a cleric.
Always healers first…
Kiril if you don’t have (m)any healers. Though consider one can never have many healers unless they have 5 maxed Rigards, Vivicas and Ariels. Then probably Triton as you have great debuffer maxed already. I am personally not a fan of Riposte, so I would advise Boril last.
Even with 40 maxed 5* and a boat-load of healers, I often bring Kiril to wars. He’s great. He can tank at 4* and perform miracles later.
Usually I would say Kiril here… but Boril has been a beast on tournament defense.
You may want Kiril for best utility all around.
I’d go Triton…great hard snipe and boosts healing from BT for whole team
One more vote for Kiril. Boril is decent, but I prefer Cyprian for riposte.
Kiril will charge at the same time as Grimm adding 30% to Grimm’s special damage. I think they would perform fine together. On the other hand, Boril, flanked by two reds is by far the best 4* tank, but not so great in any other position, so… depends on what you are looking for.
Kiril is probably the best choice when regarding overall usefulness. But Triton is more fun and the combination with Boldtusk is nice. But I would advice Triton only if you have several healers already.
One for the dwarf 
he’s very useful, I have 2 maxed and think about maxing a third one 
Kiril will be used for a very long time… and even make his way into your 5* lineups. I’d do triton after him.
My vote is also Kiril even you have BT maxed.
Kiril - Grimm = 1-2 punch
Before today I was pretty sure that it’ll be Kiril but but but… more I think about tanking with Boril more I like the idea. I could flank him with maxed Wilbur and BT. Right now I’m tanking with BT and I’m not so sure about healer tank. Maybe put Caedmon and Gregorion (3/70) to wings.
I’m not big fan of reposters but they are there for the reason and I don’t see me maxing Cyprian any time soon with Tiburtus, Sabina, Ameonna, Seshat and maybe even Quintus in line before him.
As far as riposte goes, Cyprian is a lot better than Boril, but Boril has extreme defensive stats, especially when heavily emblemed on the defensive path. I use him as tank in a world of 5* and rarely drop under 2500… Using Boril and Wilbur on the same team might not be the best idea… Wonderful Feast kind of renders Riposte useless… Two red heavy hitters flanking Boril are far better. I use Elena and Azlar. Boril has the difficult job of buying them the time to charge.
Kiril for versatility and stacking with Grimm. My Kiril + Grimm combo allows my hitters (most often Lepus or Seshat, or Triton in 4* tourneys) hit really hard. The defense buff is great too, and allows my heroes to survive hits they may not otherwise.
Triton has an interesting healing buff, but is a lot more niche (though Kiril + Triton do make an excellent combo, you could consider Triton as your next project after Kiril). With Kiril/Grimm/Trition, you can choose to use Triton to boost Kiril’s healing; or use Kiril+Grimm first to make Triton hit extra hard.
Sonya is less urgent to max because you have Caedmon already. Though you should still max her eventually, to bring against Reds for example.
Boril has a shorter “shelf life” in the long run. Best on defense and against strong bosses/enemies, but Kiril > Boril even there. Boril makes the enemies kill themselves; Kiril keeps you alive longer so you can kill the enemies proactively.
Of course, I knew that but didn’t remember… Thank you for reminding me that. Well, there is always falcon for the second red if I’ll go with Boril. I’m planning to eventually tank with Rana, but it’s going to take some time to be there.
Edit: I’m going to sleep over night but I believe I’ll choose Kiril comes morning.
Just keep in mind, Boril is a great tank, but nothing else… If you plan on using another tank, go with Kiril