The Angels really aren’t that hard to find. The hardest part about them is that you need to beat the game to access the first one. Once you’ve interacted with all four of them, go to the Tree of Life, and a cutscene will trigger which will show the Angel ending.
Chapter 1 – After the Spider’s Lair. You see her through a crack but are unable to access her due to rocks being in the way. After you’ve beaten the game, the rock pile will be cleared and you can go through and find her.
Chapter 2 – In the Fractal Forest, if you go to the Golden Martyr Statue cave, exit it and follow the right-hand wall around two corners, and there will be a stairway leading up to the Angel. If you are at the beginning of that area, try to follow the right-hand side for a while, and you will eventually find it.
Chapter 3 – In the final section of Chapter 3 in the Forsaken Kingdom, if you hug the left-side wall as you exit the last building (the building with the large golden statues), you will be able to wrap around the side of the building. If you continue to follow this path, you will eventually reach some branches; keep following these, and eventually, you will find the Angel.
Chapter 4 – There are two exits out of the Forgotten Caves, leading to the desert. One is on the right side and is full of statues and people hung up between pillars. If you go to the one on the left side, you will find that you are walking along a long hallway before reaching the exit. If you turn right halfway through this hallway, the Angel will be clearly visible in her own hallway.