Hii you can get the Ash secret ending after finishing one playthrough and selecting the choices below (spoilers):
Choose "I can't risk changing the plot" and then pick these:
Choice 1:
"Squeeze his hand." +1
"Keep staying still."
✦
Choice 2:
"How did you know I left?"
"Ash...?" +1
✦
Choice 3:
"The speed of the rebellion..."
"Ash..." +1
✦
Choice 4:
"You're insane."
"I won't leave you, then." +1