And I couldn't find a way to post this at the actual Feedback & Suggestions Forum.

Basically, any. 

There's one reason I stick to Raids despite all the negative perception it has online, and it's its themes.

All gacha games are pretty much anime or cartoonish. The only other similar game to this is Age of Sigmar Realm War, which is heavily based on a high-fantasy theme. Which is cool, but looks too stylish and way too fantasy-esque.

I love the old "Sword & Sandals" style of Raids, with a few minor exeptions such as the Dwarves. I don't like dwarves. Except for Maulie and Trunda, that is. But the rest of champs and monsters look like something from an old Conan The Barbarian movie, and only as high-fantasy as in the Lord of the Rings. 

Definitely, I do enjoy watching the models, which thankfully have a full 360° model viewer. 10/10 will come back again.

HOWEVER, he's the kicker, I don't know exactly who the champions are, why are they at it, and what they are like. 

Listen, I don't really care for re-skins. Not all armies can be made out of unique heroes. Some are just there because modelling unique soldiers takes forever. But for those unique, named champs, I'd gladly come back for some lore.

Even the simpleton re-skins might as well help flesh out the faction's lore such as army composition, cultural identities, general mindsets, etc. 

I don't care for a Lord of the Rings epic, or a deep-and-convoluted plot such as Game of Thrones. Still, something besides a random illustration of some of the characters hanging at the tavern, or being lovey-dovey with each other (besides the lover's mechanic) is appreciated. Also, kudos to the guys who make the illustrations. They actually inbue the models with more life than they're currently displaying.

TL;DR: Write some lore for the characters. Not necessarily a timeless epic, but still something readable.