With those 4*s I would run Caedmon/Boldtusk/Boril/Hu Tao/Tibertus as a good all-purpose rainbow team. Of course if you are raiding someone with a skewed team or doing a level with only one color of minions then you should double up on the strong color if possible.
I don’t believe that people would run 2-3 yellows against any titan other than purples. The main reason yellow often appears, however, is because Wu Kong is incredibly powerful against all colors of titans. Even against yellow titans I prefer to run Wu and double purple, voiding one of green, red, or blue instead.
I’ll refer you to Anchor’s hero guide, since he does a good job spelling out which heroes are best in each situation.
In general it’s good to have 2 heroes of each color so you can double up on any color. I personally like:
Purple: Tibertus, Rigard
Yellow: Wu Kong, Li Xiu
Blue: Kiril, Grimm
Green: Caedmon, Melandor
Red: Boldtusk, Gormek
Some others are great situationally, like Colen or Cyprian for defense.
vs TITANS
vs RED 34567
vs BLUE 12357
vs GREEN 12457
vs PURPLE 34567 (5 if “Grimmless”)
vs YELLOW 13457 (7 even vs yellows)
DEFENSE
14357
I don’t know for the other two but for sure one is Wu Kong. Wu Kong, Jackal and the bald monk are the famous yellow trio known for violence against purple titans.
BT needs to be with every titan. I’ve tried leaving him out vs blue and damage goes down, assuming you’re smart about using your specials. Also, BT, Wu Kong, and Tibertus should come in vs every titan, regardless of color. The combination of BT’s buff, Tib’s defense debuff, and WK attack buff is where most of your damage comes from.
In general people bring 2-3 of the color that’s strong vs the titan because the tiles are 2x damage and take out the weak color hero because they only do 50% tile damage (unless they have a necessary special like Tibertus).
having said that, here’s what I’d do with each color titan (assuming those 4* heroes are all max 70)
Blue: BT Wu Tibertus Caed Skittle
Red: Blue: BT Wu Tibertus Boril X (X = your highest attack 3* max 50 blue like Ulmer…if none Hu Tao)
Green: BT Wu Tibertus <next highest red 3* assuming it’s max) Caed
Purple: BT Wu Tibertus Hu Tao Caed
Yellow: BT Wu Tibertus Caed <next highest purple 3* assuming max 50>
From my test leaving a weak color Boldtusk for a strong green color greatly improve titan’s score.
Edit. Boldtusk dies faster without Boril’s defensive buff
If you’re talking about vs a blue titan, you don’t leave out a 2nd Green, which is strong, you leave out Boril, which is not that strong.
Boril doesn’t give a defensive buff at all or do anything to keep anyone alive - he just reflects some damage via Riposte. I think you’re confusing him with Kiril.
every titan I would use a defense debuffer yes, even if it was weak. But if you have two of them leveled, you will always have one that isn’t weak vs that titan.
FYI Grimm is normal damage vs blues. He’s strong vs Red and weak vs greens.
My tests were not based with boril but with kiril.
With this in mind every team i wrote before in this post should be revised with the exception of the defensive ones.