Nekotenguu Hanako

Always wearing a maid outfit and cleaning restrooms has earned Hanako the moniker “Maid Hanako.” Her usual mode may be being inexpressive in both face and voice, but her actions are often wild and unpredictable.

She’s actually a spirit called a "shuihu". As well as being a water god’s personal messenger, she is the master of the Nekogawa River, leader of a band of red kappa, and kind of a big deal. Thanks to all this, she’s well informed about the goings-on of the area. And when it comes to gossip in the school, she’s got all the facts. The deck brush she carries may be the most powerful weapon in the world.

How does her constant testing of the protagonist’s mettle fit into her goals?

From Steam