Unlike every other show where the devil is made out to be the villain, portrays him as a good guy. He remains a pleasant fellow who doesn’t condone killing or hurting others, while always being honest about his motives. However, that doesn’t mean Lucifer hasn’t done bad things at all.
Over the seasons of the show, the devil has engaged in things that can’t really be considered as actions of a good person. These tend to go unnoticed due to the fact that he’s always made things right in the end.
Plotting To Overthrow God From Heaven
After reconciling with his mother and brother, Lucifer took advantage of both their issues with God to plot a plan against his father. Although he planned not to enter Heaven himself, Lucifer was aware that Goddess’ anger with her ex-husband would most likely mean calamity in the universe.
And yet, he was prepared to let the host of Heaven suffer God’s potential demise if it meant he would be left in Los Angeles. This was very selfish of him, especially considering the consequences this would have brought.
Torturing His Mother In Hell For Millennia
Believing Goddess to have played a role in his own banishment, Lucifer had no problem letting his own mother be tortured in Hell. What’s more, he got Maze to inflict a specific kind of pain to her, displaying Lucifer’s ruthlessness.
When she finally returned in Season 2, it was clear that Goddess did genuinely love Lucifer. This retroactively makes his millennia of punishment toward his mother particularly malicious, seeing as Lucifer didn’t bother to make things clear with his mother for centuries.
Leaving Chloe High And Dry
Lucifer has messed up chances to make his romance with Chloe official. This was especially striking in Season 2, where, upon realizing that God had set her birth up specifically, he abandoned Chloe just when she was prepared to be with him.
Lucifer continued to leave her high and dry later as well, as he refused to acknowledge his feelings in Season 3 but interfered in her relationship with Pierce. There might have been reasons for him hurting her, but Lucifer definitely did do Chloe wrong multiple times.
Viciously Insult Amenadiel's Purpose In Life
Although they’ve had their fair share of good moments, Lucifer isn’t above hurting his elder brother. Angered that Amenadiel had faith in God once again, Lucifer went low on his insults by spitting on everything Amenadiel stood for.
Comparing his brother to a man he had once tortured in Hell, Lucifer called Amenadiel a pathetic failure whose existence was worthless and whose powerless state was a disgrace. Amenadiel was visibly in tears, and only due to his faith in God did he manage to overlook this very personal insult coming from his own brother.
Killing His Own Brother
It appears Lucifer always treated Uriel, one of his many siblings, rather unwell as Goddess revealed he didn’t let Uriel him and the elder angels in their activities. Lucifer made this worse by going so far as to killing his own brother.
Of course, this was due to Uriel wanting to finish off Chloe and Goddess, but he had also made it clear that he had no intention of taking Lucifer’s life. Uriel was also heartbroken when Lucifer stabbed him with Azrael’s blade. It’s clear from Uriel’s death being Lucifer’s personal Hell that Lucifer himself believes this to be the worst thing he’s done.
Make A Mockery Of Daniel's Misfortunes
One can always count on Lucifer to throw out witty insults at anyone, but he was particularly nasty towards Daniel in earlier seasons. Despite knowing that Daniel was suffering through a painful divorce, being demoted, and his general lack of self-esteem, Lucifer made it worse by throwing jabs at him.
Being called “Detective Douche” was hardly a fun thing for Daniel, which went ignored by Lucifer. Of course, he stopped with these insults once he became friends with Daniel, but Lucifer did annoy him during his lowest moments.
Influencing People To Follow Their Morally Wrong Desires
It’s usually by coincidence that Lucifer’s advice benefits people whom he encourages to follow their desires. However, influencing morally wrong decisions has also led to bad results. While Lucifer doesn’t force anyone, he does heavily involve himself.
One of the more significant consequences was Dr. Linda almost losing her practice, as Lucifer’s initial seduction of Linda put her ethics under focus and it was Maze who bailed her out. Other instances involve Lucifer encouraging people to cheat on their spouses if it means they get pleasure out of it, even though that’s not the right advice to give.
Painfully Kill Cain Just To Spite His Father
Cain ended up being one of the villains, although Lucifer’s attempts to kill him had nothing to do with this. His original interest in Cain’s death was purely to spite his father, as God had been the one to make Cain immortal.
Lucifer didn’t care about Cain’s inherent sadness at his living Hell, and didn’t sympathize with the latter’s situation. Instead, he would make jokes about it and suggest creative - and painful - ways to try and kill Cain to feed his own father issues.
Ignore Maze's Feelings Of Abandonment
Maze had been Lucifer’s protector and closest friend for centuries by the time the show’s events began. And yet, Lucifer was quick to lose interest in her once Chloe came into the picture, following which Maze was left feeling lonely and abandoned.
Her attempts to talk to Lucifer were also met with barely any interest on his part, which was very tactless since she had looked out for him more times than anyone could count. Considering Maze - who hardly ever showed her true emotions - felt so hurt, Lucifer ignoring her feelings was a jerk move.
Becoming Corrupted Under Eve's Influence
After reuniting with his original lover, Eve, Lucifer started to overlook what he’d learned about empathy from his adventures with Chloe by beginning to embrace his devil side. This led to his angel wings transforming into devil wings.
One of the most ruthless displays was when Lucifer attacked the human trafficker Julian, to the point where the latter was crippled after Lucifer crushed his spine. The man may have deserved it, but Lucifer’s sadistic pleasure at doling out such justice hardly stemmed from benevolent intentions.