The best fictional character is a tricky question to answer because it is subjective. What might be someone's favorite character may not be someone else's.
That being said, some of the most renowned fictional characters include Batman from the DC comics, Harry Potter from the world of Harry Potter and Rick from Rick & Morty.
Batman is a superhero who has become an iconic character in many cultures around the world. His backstory about being a billionaire and using his money, intellect and martial art skills to become a protector of Gotham City is one that resonates with many fans. He is also susceptible to making mistakes, which makes him relatable and further deepens the character.
Harry Potter has also become an immensely popular fictional character. His story of an orphaned boy who discovers his magical powers and attends a wizarding school captivated the imaginations of book readers and movie-goers alike. Harry's story, filled with suspense and intriguing twists, is something that continues to latch on to new generations of fans.
Rick from the popular cartoon Rick & Morty is definitely one of the best fictional characters. He is mostly an anti-hero and has some lovable yet abrasive qualities which draws people to him. He is an advanced mad scientist/inventor who often gets into serious and silly adventures with his grandson, Morty.
In conclusion, all fictional characters have something unique to offer and there is no single one that is better than another, as this is highly subjective. That being said, characters such as Batman, Harry Potter and Rick from Rick & Morty all have plenty of qualities that make them stand out and loved by many.