This is the best political story game on Mobile
While there are other games such as Suzerain (and probably many others unknown to me), I genuinely think this game is a masterpiece in its political intrigue and story.
It's "Yes, Your Grace". Its pixel-based setting gives it a nice touch, and it's very beautiful artistically.
You play as the king of a moderate kingdom. You face difficulties with other tribes and matters of the kingdoms. You also have to make strategic choices because, literally, every choice will have an effect on the story. The stakes are high right from the start.
And yes, in this cruel medieval world. you'll have to marry off your daughters to make alliances with other kingdoms. And yes, this game can make a grown man cry.
Though it's not free, it has a demo that you can try. It's available on Mobile and PC (Steam). It also has a sequel: "Yes, Your Grace: Snowfall"