As you progress in the game, you will be able to improve your relationships in the survivor village. The combined score is your reputation - your reputation rank is how to unlock different endings. A lower reputation unlocks shorter endings with less resolution. To get the "True" ending, Adol must defeat the final Boss with approximately a 200 reputation. To earn reputation, open the side quest tab to see what missions are available. Each playable character has several side quests. You can also talk to Dogi and complete his missions to increase your reputation score. Some side quests are timed. Always complete timed missions when they appear. When the timer stops, you will not get another chance to complete them. If you skip too many, you may have to restart the game to get the "True" ending.