I have managed to find decent teams against blue, purple and red titans at this stage, but really struggle against yellow and green. My ally fights mainly 4*, we just recently had our very first 5* (that escaped).
Here are my heroes;
Any help would be really appreciated 
Basicly you want Wu-kong(or Tarlak/Miki/Ranvir/Gazelle) and 4 heroes strong for titan (best with def down and atk buff)
For now
Green
Scarlett-Hawkmoon-Nashgar-Azar-Valen
Yellow
Sabsy-Proto-Baltazzar-Renf-Valen
I would go rainbow for now against all titans.
Then take the weak one out and put a 2nd strong inside of your team.
Hawk Bria Val Sabs Bane
Holy titan: Bane out - Balth in
Nature titan: Val out - Scar in
That strategy worked well for me in the beginning. Later on mono strong or 4 and an att buffer.
After some 4* maxed:
VS Green: Boldtusk (replaced Hawkmoon costume) , Gormek (replaced Valen defdown), Scarlett, any rest strong red…
After some 4* maxed:
VS Yellow: Boldtusk - Gormek - Sabina - Proteus - Balthazar
OR
Kiril - Grimm - Sabina - Proteus - Balthazar
Gill ra will drop attack and defense… I’d consider her for holy titans. Proteus has solid attack stats and his special is def nice.
These are listed in no particular order, and consider only heroes you have. eventually you will want to try and go 4-1 striong color, or at least 3-2.
For Green you want to get to this as you strong color 4, this gives an attack buffer, and defense dropper:
Boldtusk - Scarlett - Nashgar - Gormek
Right now it should be:
Hawkmoon costumed - Scarlett - Nashgar - Azar plus Valen
For Yellow you want to get to this as you strong color 4, For Green you want to get to this as you strong color 4, this gives a defense dropper:
Proteus - Sabina - Balthazar - Gill-Ra
Right now it should be:
Proteus - Sabina - Balthazar plus Valen & maybe Brienne or (ick) Renfeld
Good luck.
