Names like 'Cipher' are great for a mystery story as it implies secrecy and mystery. 'Enigma' is another one that really shouts mystery. And 'Inspector Locke' is a name that gives the impression of a serious investigator. Locke also has a sense of something locked away or hidden, which fits well with the mystery genre.
Some character name ideas for a fantasy story might be 'Orion'. It's a name from astronomy, but in a fantasy context, it could represent a character who is a great hunter or has a connection to the stars. 'Nymphadora' is a more elaborate name that brings to mind magical creatures like nymphs. And 'Gryphon' could be used for a character with a mix of noble and fierce qualities, inspired by the mythical griffin.
You could call it 'The Enchanted Forest Adventure'. It gives the idea of a story set in a forest full of magic and mystery. Maybe the main character is a young explorer who stumbles upon this forest and has to face various challenges and meet strange creatures.
Consider 'The Hidden Doorway'. This title is very evocative. It could lead to a story where there is a door that is hidden in an ordinary place, like in the back of a closet or under a staircase. When the main character discovers this door, they enter a whole new world full of different rules and beings. For example, it could be a world where animals can talk and magic is real. The character then has to navigate this new world and figure out how to get back home if they want to.
You could name it 'My Secret Chapter'. This gives a sense of it being something personal and exclusive, like a chapter in your life that only you know about.
In a detective story, names matter. 'Griffin' could be a name for a shrewd detective, it has an air of intelligence. 'Natalie' is a common but effective name for a detective's assistant, perhaps. And 'Dexter' has a double meaning, it can imply someone who is dexterous in solving crimes but also has a bit of an edge.
Some more name ideas for your fantasy story are 'Faye', which is short and sweet and gives the idea of a fairy - like being. 'Cassius' has a strong and somewhat menacing sound, ideal for a villain. 'Avalon' is a well - known name from Arthurian legend and can be used for a magical place or a character with a connection to that kind of mythology.
The Shadows. It gives a sense of mystery and secrecy, like a gang that operates in the hidden corners. They could be a group that has some sort of shadowy power or ability in the story.