Character concept:
An oracle who relays messages they don't understand, to people whom they don't know, through graffiti. Most of it seems like completely random nonsense, in completely random places, but whatever compels them to write this instruction in this exact place ensures that whoever needs to see it will see it at just the right time, and make the right choice.
Not knowing the question, only the answer, the oracle frequently feels compelled to write these messages, such as "turn left", "no", "the greener one", "it's in his shoe", "garlic bread", or "the dog knows", to random things and places like on a trash can, on the bottom of a park bench, on a post-it note in the bathroom of a coffee shop. The oracle doesn't know that these messages sometimes solve matters of life and death.
And at one point while on a walk, passing under a bridge, the oracle feels compelled to write, "stop searching for these. You will not find me this way." And then, on the complete opposite side of the city, they see a bicycle, can sense that this is a place for a message, but this time one isn't dictated - they can freely choose what to write. And this time, they vaguely know whom it's for. So the Oracle leaves a message.
"I would like to be friends, though."