The Gundam series has TONS of them.
- In Mobile Suit Gundam, Gihren Zabi crosses it either when he kills his father and blows away his fleet with the Solar Ray to prevent him from negotiating an end to the One Year War, or when he takes being compared to Adolf Hitler as a compliment.
- Mobile Suit Gundam: The Origin:
- Operation British is given such a gravity and focus in this adaptation of the story and The Origin very clearly highlights the scope of the atrocity. The thousands killed by the gas, the millions killed by the Colony's drop, and the lack of remorse that Gihren had in masterminding the whole thing. Ramba Ral is immediately repulsed upon hearing about the plan and bails even if it means being demoted, Degwin loses faith in the Zeon ideal right then and there, and its one of the major reasons why Revil refuses to agree to Zeon demands as he'd be submitting to monsters like Gihren.
- Kycilia ordering the bombing of a domestic cruiser because of reports that Casval was aboard. Over fifty innocent people are killed, including the original Char Aznable; and the losses mean nothing to her.
- Ginias Saharin of Mobile Suit Gundam: The 08th MS Team has his MEH when he kills his commanders after realizing leaving Earth means ending the Apsalus Project.
- Captain Ethan Ryer crosses it when Aina Saharin asks for a brief cease fire to get wounded soldiers out of the battlefield, he gives it... then has a GM Sniper set up and destroy the Zanzibar transport they were on.
- Anaval Gato of Mobile Suit Gundam 0083 has his when he fires the GP-02A's Atomic Bazooka.
- In Mobile Suit Gundam ZZ the Dublin Colony Drop serves as an MEH for Haman Karn (who ordered it), for Mashmyre Cello (who aims the asteroid), for Rakan Dakharan (who shoots down transports and destroys bridges to make sure no one can escape) and for the EF officials (who stand by and let it happen).
- Mobile Suit Gundam: Char's Counterattack:
- After previously shifting towards an Anti-Hero role in Mobile Suit Zeta Gundam, Char crosses the horizon for good in the opening of Mobile Suit Gundam: Char's Counterattack with the Colony Drop of Fifth Luna, cementing him as beyond the pall.
- Char's Dragon, Gyunei, ends up crossing the MEH as well. At some point he defeats and captures Amuro's wingman and the local Action Girl Kayra Su, forcibly pulling her out of her cockpit and keeping her hostage in his Jagd Doga's hand. He then stages a Hostage Situation to try getting Amuro and the Nu Gundam to surrender; when the funnels of the Nu accidentally react to Amuro's anger over it, Gyunei uses the Doga's hand to crush Kayra to death, then tosses her lifeless body aside like it's nothing. Amuro, understandably, is PISSED at that.
- Ulube Ishikawa and Dr. Mikamura have theirs in Mobile Fighter G Gundam when they attempt to capture the Devil Gundam for their own uses, which leads to the death of Domon's mother, the imprisonment (and silencing) of Domon's father, and Kyouji becoming the Core Unit of the mutated Devil Gundam. When the end result of all of this leads to Dr. Mikamura's innocent daughter Rain becoming the Devil Gundam's core , the second in the list ends up having a Heel Realization and, having been shot by the gleeful Ulube, with his dying breath he begs Domon to save his daughter and releases Domon's father's capsule, which allows Domon's friends to rescue him.
- The Frost Brothers of After War Gundam X probably reach theirs after killing off a group of people in an attempt to awaken their Newtype abilities. When they do with one person, they kill him as well out of sheer jealousy.
- Mobile Suit Gundam SEED has PLENTY here. Captain Sutherland and the Earth Alliance in general by nuking their base with a lot of their allies in it, ZAFT soldiers killing POWs after said incident, Muruta Azrael after convincing the EA to fit N-Jammer Cancelers onto their nuclear missiles and promptly launching them into every hole within the meteor base Boaz... Patrick Zala's is killing off the Moderates within ZAFT (including Lacus Clyne's father).
- Continued in Mobile Suit Gundam SEED Destiny. Lord Djibril sends the Destroy Gundam to attack European cities because they won't follow Blue Cosmos. Then comes his plan on using Requiem on PLANT colonies.
- And we may have a winner here with Ali Al-Saachez from Mobile Suit Gundam 00. he starts by recruiting Kurdish kids into a jihadist army while posing as an iman. The only requirement for joining is that they murder their parents first. Then he sends several of them out into the world to do suicide bombings. And when things go sour, he just packs up and leaves them to be crushed by the enemy mobile suits. The icing on the cake is that he didn't given a damn about the cause – he's an atheist who only used religion as a means to manipulate people for his own depraved goals, so to speak. And this is all before the story even started, where he gets many, many more opportunities to show how much of a dick he can be.
- Not too far behind Ali we find the A-laws, who have no trouble at all with firing their orbital Wave-Motion Gun at a solar elevator, to kill the rebelling forces inside, the 60,000 civilian witnesses, and the hundreds of thousands of people living below who will be crushed by the falling debris, just to prevent the populace from learning of their previous misdeeds.
- Nena Trinity doesn't mess around with crossing the line as well. Out of boredom and hatred to those not playing by Trinity's rules, she vaporized a wedding in Spain (Louise Halevy was the only known survivor). With her Lack of Empathy and having zero regret over this incident.
- Ribbons Almark himself crosses the line switch the reveal in Season 2 that he was the one who ordered the many horrific atrocities in the series from the A-laws' brutal purges to Ali's destruction of Azadistan.
- Gundam AGE has Desil Galette crossing the line in episode 14: for manipulating and then killing Yurin for the sake of defeating Flit, then justifying it by saying that her life didn't matter, she was nothing more than another weapon/toy for him to use, and that her involvement and death just served to make things more fun! All this from a 7-year-old child. These events lead to most of the fandom screaming for his blood.
- The third season adds one from Zeheart Galette, ex Anti-Villain, who commands the destruction of Kio's home colony. And then there was Episode 48, where he sacrifices a large portion of the Vagan forces in an effort to destroy the Diva and Gundams. In-universe, everyone was understandably horrified.
- Mobile Suit Gundam: Iron-Blooded Orphans:
- Rustal Elion gets his early on, when he attempts to have the Prime Minister of Arbrau assassinated in order to trigger a war between Arbrau and the Strategic Alliance Union. This only a few episodes after he claimed to be committed to upholding peace and order.
- Iok Kujan crosses it first by ignoring Turbines' surrender signals and then ordering a Dainsleif barrage on the vessels carrying the Turbine wives and children.
- Jasley Donomikols is a detestable character from pretty much the instant he appears, but the moment he crosses the line comes when he has Lafter murdered, and then implicitly threatens to do the same to the rest of the surviving Turbines, in order to goad Tekkadan into a confrontation with him.
