Ichibu Morin-oni was the founder of Nozomigakure He had the ability to transmigrate to other bodies and do what they needed. This is where the myth of him showing up when you need him came from. The person who needed assistance needed to have the Nozomigan activated for him to do the trasnmigration technique.
Tenshi Mori-oni is the daughter of Ichibu Mori-oni and is the current Nozomikage. Her name completely contradicts itself; it means 'Angel Helping-Demon.' As strong of s shinobi she is, she is completely unstable. When she activates the Nozomigan she goes berserk and will hurt anyone near her; friend or foe. To stop this, she created her own technique so she doesn't have to use the Nozomigan. The justu is called the Frame Technique. It is called this because she literally makes a camera made of chakra and takes a photo of her enemy and seals their opponent in the photo. This techniques requires little chakra but is extremely hard to master.