Since I haven't read it, I can't say for sure. But based on the title, the main characters are likely to be the 'oroka na tenshi' (the naive angel) and the 'akuma' (the devil).
As I haven't had the chance to read this light novel, it's difficult to name all the main characters accurately. But from the title, we can assume that the two central characters are the angel, who is characterized as 'oroka' (foolish or naive), and the devil. There may be other important characters that are introduced as the story progresses, perhaps other angels or devils, or humans that get caught in the middle of the relationship between the main angel and devil characters.
Chapter 456, "It's Not Too Much to Ask for a Game Console, Right?", is the clearest early answer because it turns Zheng Xun's situation into a concrete plot event. Early on, There was no choice but to follow through with the rules she'd set,....
Chapter 123, "Can This Even Be Calculated?!", is the clearest early answer because it turns Is Jiang Li's situation into a concrete plot event. It opens with After He Yun also carefully rolled up her trouser legs and walked...
Chapter 615, "River·Doraemon·Li", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Everyone huddled close with their bowls in hand.
Chapter 459, "Even Got Educated by a Variety Show", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Su Yinwan felt somewhat annoyed but could only suppress the emotion...
Chapter 305, "Sorry Zhou, please forgive me!", is the clearest early answer because it turns Wenqi Zhou's situation into a concrete plot event. It opens with South District is the most remote area on the outskirts of the...
Chapter 328, "Persuading the Old Master", is the clearest early answer because it turns Grandfather's situation into a concrete plot event. Early on, Jiang Li's authoritative words stunned the old man.. By the end, This one is her father's list of failures to comply with credit, and....
Chapter 292, "Coming and Going, Gathering and Parting, Human Nature", is the clearest early answer because it turns Parting's situation into a concrete plot event. The chapter turns that into something concrete by moving from Jiang Li slowly lowered his hand.
Chapter 443, "Did Jiang Li Steal Team F's Home?", is the clearest early answer because it turns Feng Shui Array's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Team D's captain, curious, turned around and was surprised to find...
Chapter 305, "Sorry Zhou, please forgive me!", is the clearest early answer because it turns Zhou's situation into a concrete plot event.
Chapter 478, "Someone Comes to Bully Me?", is the clearest early answer because it turns Cheng Biao's situation into a concrete plot event. Early on, However, before Jiang Yan's axe could descend, he heard a rustling....