Mori, the Port Mafia's leader, is strong enough to curtail Raynare and get her to agree to work for him without even needing to attack her, just using his sheer killing intent to cow her. She even compares his level of bloodlust to Kokabiel!
After the U.A. Entrance Exam, while hanging out at Dagobah Beach, Izuku, Ibara, and Ochako come across Itsuka Kendo being threatened by a trio of drunk guys who are trying to force her to have sex with them, and that they'll make her if she turns them down, even mentioning that she'll get in trouble if she uses her Quirk to defend herself. Luckily, the devil trio shows up and manages to scare them off.
The USJ incident becomes worse for several motives:
Rather than just bringing in several Mooks, Shigaraki went and brought Muscular.
The Noumu is heavily implied to be Riser and Ravel's brother, meaning that the League is experimenting on Devils as well as humans. And the Phenex flame regeneration makes it powerful enough that, even though All Might still has One For All, he has even more trouble beating it requiring a total of 500 blows to defeat it.
Bakugo stumbles onto Freed murdering a priest and gets shot repeatedly. If Azazel hadn't saved him he definitely would have died.
Xenovia pisses off Akutagawa when she tries to attack him, only to fail to do any damage become he's using a Quirk, not a Sacred Gear or magic, and she would have been seriously injured or even killed by Rashomon if Izuku hadn't intervened, and he gets part of his wing torn off for his trouble. Fortunately, he can get that healed with Phenex tears, but he still has a huge scar left, and had he timed it just a little differently he would have lost an arm, and he can't regrow those.
Everything about Lailah. The fact that she's deliberately based on Airachnid from Transformers: Prime, complete with a similar history with Griselda that Airachnid has with Arcee, should tell you a lot about her, and none of it good.
She's first mentioned by All For One's doctor, confirming that she has ties to the League of Villains.
She first encounters the ORC when they're hunting a stray devil, only she got to it first. When they investigate the warehouse that she's in, they find that it's full of human corpses, and she expresses a desire to kill Ochako and add her witch body to her "collection".
The worst part of it all? She's an angel, who has avoided Falling due to Loophole Abuse, having been created to be a Torture Technician for God during the Great War, and has been freelancing since the war ended.
As the Sports Festival ends, Stain is approached by Lailah, and then the League shows up, looking to recruit the former...