Len is a Japanese game developer who has created several shooting games using Danmakufu. He's notable for his style of gameplay that takes inspiration from arcade danmaku games, particularly Cave shooters. Although he's created many games that aren't directly related to Touhou, he is most known for his Touhou fan games, Phantasm Romance and Phantasmagoria Trues.
- Len 9: To the Ends of Phantasm, an endless danmaku game.
- Len 11: Phantasm Underworld, a three-stage game that awards players for defeating enemies when there are many bullets on screen.
- Len 12: Phantasm Another World, an extra stage for Phantasm Underworld.
- Len 15: Phantasm Romance, Len's first full Touhou game.
- Len 17: Phantasm Underworld ―Re:F/Rain―, a remake of Phantasm Underworld.
- Len 18: Last Word Spell Card Collection, a collection of last words featuring various Touhou characters.
- Len 20: Phantasmagoria Trues, a remake of Phantasm Romance.
- Len 20x: Phantasmagoria Trues Last Words, a collection of last words to go along with Phantasmagoria Trues.