On the surprise night, when he comes back from home and opens up the door, he finds a young girl with a fox ear and a tail named Senko.
She loves to do cleaning for him, give him a massage, help him in his grooming, and give him lap sleep time.
She is another Kitsune who is sent to assist Kuroto because of Senko’s difficulty to help him relieve his stress.
She is shown as a messy and lazy person who eats microwave-ready meals and once in a while cleans her home.
This speculation lies on many facts, one of them is the popularity that the show has gained after it was aired.
I hope you have got much insight into “what Senko San is”.
So taking no more time of yours, go and watch this series.