All these scenes triggered inside Ancient Battlefield (New Game+), hope this help you guys
S1: Gaki map, just run into them multiple times, its a rare encounter (not sure if its available or not at the map right after we enter the Ancient Battlefield, try from the 2nd or 3rd map)
S2: Youkai Flower map, the map right before you enter Abura-Sumashi map. Try looking at the left side, there's a tree with a spider web
S3: Kakuen map, lets start from right before you enter the temple with 2x Red Oni, run back 2 maps, there's only one house in this map with a smoke-leaking gas stove inside
S4: Possessed Corpse map, rare encounter
S5: Kappa map, try running around, there's a special treasure on the lower ground which is pretty easy to notice
S6: Spectral Snake map, keep processing with the bottom left road after you left the Kappa map, u will eventually run into 3 NPC kids
S7: Burning Wheel map, there's a flicker on the road right after you entered Burning Wheel map, pretty easy to notice
S8: Undead map, rare encounter
S9: Mud Fiend map, try running around, there's something red (i'm not sure what it is) above a pond, pretty easy to notice
S10: Villager map, go left to the 2nd map after you left the cave, it's inside the bathroom of the right house
S11: Villager map, this time go down after you left the cave, there's a flicker on the road
S12: Mud Fiend map, try running around, there's a blue-hair NPC standing next to a pond
