Maus can be considered a true story. It's a powerful portrayal of the horrors of the Holocaust as recounted by the author's family, but like many works of this nature, it may have some elements of interpretation and fictionalization to make it more accessible and engaging for readers.
Well, Maus is a non-fiction book mainly because it presents factual events and personal accounts related to a significant historical period. The author uses the graphic novel format to convey real-life circumstances and emotions.
One similar book is 'Persepolis' by Marjane Satrapi. It's also a graphic novel that tells a personal and historical story. The author uses her own experiences to give an inside look at life in Iran during a period of great change and turmoil.
Definitely, Maus is fiction. It creatively represents historical circumstances in a way that blends imagination and factual basis to tell a powerful story.
To a large extent, Maus is real. It draws from the author's father's accounts of his experiences during the Holocaust, but it also uses artistic interpretation and narrative devices to convey the message.