Help finding 2020s mobile RPG game with hero collection and zombie combat in post-apocalyptic setting

I’m trying to remember the name of this mobile game I played a few years back. It was an RPG where you could gather different characters and battle against zombies in what looked like a destroyed city environment. The game had a really unique art style with bold black borders around everything. You could join guilds with other players and there were both player vs player battles and story mode fights that would happen automatically. I think the app icon was mostly yellow colored but I’m not completely certain about that detail. The whole game had this dark atmosphere like the world had ended or something. Does anyone know what game this might be?

Sounds like State of Survival. It has that zombie vibe and lets you collect heroes.

You might be thinking of Dead Trigger 2 or Last Day on Earth. They both have that zombie apocalypse vibe, but I’m not sure about the hero collecting element.

Sounds like AFK Arena. It’s got that comic book style with black outlines, hero collecting, and auto-battles. Can’t remember if it had zombies though - might be thinking of a different mode. The yellow icon rings a bell but I’m fuzzy on mobile games from back then.

Maybe The Walking Dead: Road to Survival? It’s got hero collecting and guilds in a zombie apocalypse setting.

That black outline style sounds like Brave Nine or Epic Seven, but neither has zombies. Maybe Girls’ Frontline? It’s got the post-apocalyptic vibe and hero collection, though you’re fighting machines instead of zombies. The yellow icon’s tricky since most games swap their icons for events all the time.