Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.
Light Novels/Anime
- Episode 1/Volume 1, Diablo has his first outing as an actual Demon Lord. Having No Selled an attack by a Salamander summoned by a racist Jerkass, Diablo proceeds to use an One-Hit Kill style Explosion on the summon that that Megumin would be proud of (and probably in awe of too).
- Diablo shrugs off the elf squads' arrows, especially a special holy arrow. He then unleashes a hellish winter to stop them.
- Edelgard gets a villainous one where before she invaded Faltra City, she had the foresight in sending in a sleeper agent to take out Celes. It could have worked if it weren't for those meddling girls and their OP Demon Lord, who once he heard about the sleeper agent, flat-out nuked the entire army with White Nova. Edelgard gets another one when she survives the White Nova that vaporized her army with little more than Clothing Damage.
- Say what you want about Emile, but it took a big pair to take on a very powerful Demon wizard that just decimated most of the Adventurers. And to his credit, he lasts long enough to allow Diablo to come back, who assures him that he was a hero today.
- Even before this, the expression on Diablo's face when he arrives. If looks could kill, Gregore wouldn't have gotten a word out...
- Diablo finally gets a weapon that will help dampen his powers enough so that he won't kill his opponents. This means he can go all out whenever and wherever he wants.
- Rem knocking a cowardly bounty hunter to submission with a single punch, after appearing behind him out of nowhere.
- Emile doing a Big Damn Heroes and saving Shera, saving Diablo the trouble. He may be overblown, but his heart is definitely in the right place.
- Having recovered from his Heroic BSoD, Diablo heads straight to the Elf army's camp and wipes them all out. When he sees Shera in distress by her monster of a brother, his face shows he is not amused.
- The collars work out for the heroes' benefit. Diablo uses them to reveal Shera's true feelings, negating the spell Keera places on her to control her.
- Diablo defeating the Force Hydra. If it can regenerate any part of its limb, then might as well just roast everything in one go.
- Diablo's fight with Galford. Unlike the last time where he defeats his opponents in a one-sided battle, the Demon Lord from another world has to face someone who is nearly his equal and Diablo has just been handicapped, severely tired after a recent fight. However, Diablo already made his resolve that he'll fight to protect those he cares for. Special mention goes to his magical mines that he set up to trick Galford. There's also him having the foresight to have a backup plan in case things goes wrong and fires his lighting strikes to defeat Galford to submission.
- Simple as it is, Diablo reflects Saddler's (temporary) petrification magic against him, who very much deserved it.
- After Rem sacrifices her life to protect Klem, the demon girl is deeply enraged at this and transforms into her One-Winged Angel form to avenge Rem's death. Klem made sure that Saddler suffers despair unlike any other and gives him an unceremonious death.
- Volume 9 has a few badass moments in it. First, Galford reveals that he has a trump card up his sleeve which he uses to kill Ryoka, a Fallen that had been giving him a hard time and killed/injured several adventurers with ease. Next, Klem and Edelgard show up at the right moment when Modinalaam is ready to finish everyone off, and proceed to completely Curb Stomp the Greater Demon Lord until he goes One-Winged Angel. When Diablo shows up and sees the result of the fight, he admits that if Klem had fought him seriously in her child form, he would have lost the fight. Then Diablo, fresh off his training to become a magic swordsman, along with Rose and Sasala, a level 200 Swordmaster Dwarf (dog-eared people), proceed to clean up after everyone with ease. Finally, Rem gets one where she, after being possessed by Modinalaam, reveals that he's terrified of Elixirs, as Elixirs can cure all negative statuses, and Modinalaam is the "Demon Lord of Insanity" with insanity itself being a negative status.Diablo: No one playing the game would have tried this, Elixirs are hard to come by. Is it that simple?
- Volume 11. Rem has a nice little astral chat with a fragment of Klem. She points out that Rem's got her fangs. Gewalt, having grown bored of tormenting Rem and Shera was about to use his Ifrit to start a forest fire, after sadistically torturing Shera and Rem to death, out pops Demon-Queen Rem who delivers unto him an epic Curbstomp Battle, forcing him to run deep underground, fleeing for his life, rightly terrified of the level 130 fist-fighter he's up against.
- Volume 12. The climactic end of the volume has Diablo face four or five Evangelion-expies, complete with AT Fields. He would have been content with simply forcing their retreat, or holding them off until either reinforcements arrived or the civilians escaped, until he noticed a couple of them targeting Rem. If they had simply grabbed Rem and taken her away in the chaos, he might have forgiven that. Instead, they decided to loudly play a "how many limbs can we break before she dies-HAHAHAHA!" game, and brag about it, making her scream in pain as they went on to crush her limbs one by one. At this point, Diablo goes This Means War! and pulls out all the stops, not even bothering with the roleplay anymore. He completely disables one, blowing up the cockpit and killing the pilot in the process, and completely crushes two of them like tin cans with a single spell so powerful, they can't even dodge or run away. The remainder are forced to retreat for fear of their lives. Then after healing Rem with a healing potion, they share a Big Damn Kiss!
