During Flash's first duel with Cold Steel, he sees the perspective of the duel from his monsters, seeing through Flash Heart Dragon's eyes. But once he looks closer at his monsters Lucidum and Crossbolt and sees they are scared of the monster they are facing. Cold asks Flash if he ever considers how his monster feel about the battles he forces them into, fighting his battles for him. When Cold makes the supposed winning attack that consumes Flash Heart Dragon, Flash himself is forced to face it in Flash Heart's place and feel the fear he does for himself.
Twilight being trapped in a sealed room at the museum while slowly running out of air. Though Cold Steel claims that she was never in any real danger since he would have released the doors manually is Flash lost the duel, she was still passed out from lack of oxygen by the time Flash got to her and needed to go to the hospital.
The building falling on top of Flash during his action duel with Gizmo. The whole crowd is left silent for a moment, worrying about Flash and his safety before he reveals he is okay.
The Dazzlings are revealed to be working for Sombra, and he has given them the ability to make anyone they defeat completely obsessed with them. The depths of this were shown by Lyra's change in attitude and how she tried to copy their play style of stealing monsters.
After Aria and Sonata lose to Rarity and Pinkie, the Dazzlings barely managed to escape, only to be immediately contacted by Sombra, and he is not happy.
A gang of duelists called the Black Griffons use to be a helpful group, until a thug called Guto took over when he beat the previous leader and turned everyone into a group of thugs like him. The danger the group possesses is seen when they duel with a stolen ARC System that makes the monsters they duel with and their attacks real, causing major damage. During his duel with Rainbow and Gilda, he sends Gilda off the edge of the building they were on. Gilda was just lucky Fluttershy was able to catch her on a lower floor.
Yugioh EQG: Shadow Gates
Throughout all their duels, Adagio and Shadow constantly hurt their opponents with their final attacks. This ends up with everyone they defeat going to the emergency room, with some staying longer than others. It actually gets so bad that Shining Armor tries to make Twilight forfeit from the tournament, out of fear she will end up facing one of them and getting hurt herself.
Flash becomes so desperate to defeat Garble and his two goons that he tries to force his next Xyz monster to wake up, uncharacteristically yelling at it and his other monsters in the process. His monster eventually wakes up, but Flash gets a Super-Powered Evil Side from it, complete with glowing red eyes and a surprisingly sadistic side when he refuses to accept his enemies surrender. He ends up blasting Garble and his goons at the same time with his Chaos Command Dragon, which leaves all three of them scorched from the blast and smoking afterwards. This act actually terrifies Flash's friends since they don't know what has happened to him, and even Adagio and Shadow are a bit worried that this new monster might be too much for even them to handle.
During a practice duel between Flash and Cold, where Cold intentionally tries to make Flash mad to activate his new power, he discovers that Flash damaged his bond with Chaos Command Dragon and his Super-Powered Evil Side is actually a result of the hate that both Flash and Chaos Command Dragon felt at the moment they made their link, the hate Flash felt for Garble's gang and the hate Chaos Command Dragon felt at Flash for trying to use him as a weapon. This created a spirit of hate that takes control of Flash whenever he uses Chaos Command Dragon, and it will remain as long as their link is damaged as it is.
Throughout the tournament, Adagio is desperately trying to complete her mission and save her sisters due to Sombra punishing them for their failure. After Adagio loses to Twilight, she tries to escape from Freeze Stadium, only to be caught by Shadow and punish her for her own failure, while taunting her that at least now she will be with her sisters again.
Shadow's ultimate monster, Shadow-Mech Annihilator, is this by virtue of being a giant Expy of Unicron. It is so massive it can destroy a monster just by poking it with its finger, and even then the resulting damage is still enough to seriously injure Twilight and knock her out.
It is revealed in Flash and Shadow's duel in the finals that Shadow is actually a robot. Shadow explains that he was created by Sombra and Freeze Industries to be the ultimate Duel Bot, one that could duel like a human could by using instinct to adapt to the unexpected. But one day, in the blink of an eye, he suddenly gainedsentience and hid it from everyone but Sombra, who he saw as his father. Sombra hid Shadow and his programming away in the deepest server of the Freeze Industries computers for years, where Shadow slept until Sombra awakened him again. Shadow also claims that he was actually conscious for all those years he slept, and dreamed of becoming human for real.
It is revealed that the Dazzlings were brainwashed for their failure, robbed of their free-will by Sombra. It is shown that Thorax suffered the same fate after he was captured.
It was previously said that the strain from summoning his deck was putting a toll on Sombra's body. This is finally shown when Flash and Cold confront him in his base, with him looking like a sick old man with wrinkled skin and a scared face.
Sombra trapping Flash and using him as a battery to summon one of the last two monsters he needs for his deck, saying that he probably wouldn't have survived if he had done it himself. The process is definitely painful, since Flash's screams can be heard all throughout the base, and Flash is put into a coma afterwards that lasts at least a week. Sombra gaining this card in particular actually restores him to perfect health, making him more fit to lead his forces and get the last card himself.
Sombra: Like father like son, you both end up helping me.
Thorax's nightmare, where he is running away from a swarm of bugs and runs into the arms of his mother for safety. Except she turns into her monster, Changeling Queen, and she forcibly changes him into Changeling Drone, showing his fear of turning into a monster like her.
Sombra completely outclasses Cold during their duel, and after defeating him leaves him bleeding on the ground instead of having his tower immediately teleport him out like it would for all losers, just to use him as a warning to the others.
When Sombra loses to Flash the Doom-Vaders attempt to pass through the unstable Shadow Gate by force, which is said would have destroyed the Earth, Spirit World, and dark world they were imprisoned in the process.
Yugioh EQG: XX
Moondancer's sudden death. She ends up sleeping in and runs late for her meeting with Twilight, and due to nothing but some bad luck she gets hit by a car and dying upon impact.
Marble Pie having a Soulink forced on her. The process is not a pleasant sight, with the feeling of being ripped in half she is torn from her own body like a ghost and chained to a stone tablet while her real body is taken over. This is after it was previously said that a "Soulink" was a "great miracle" by Saltalunam.
The Adult Fear of Pinkie and Maud not noticing immediately that something was wrong with Marble when the spirit pretends to act the way she does. It is essentially the same as a loved one not noticing you have been replaced with an imposter stealing your identity.
During the Climax Duel between Flash and "Marble", when "Marble" gets mad over Flash managing to survive her attack Flash is able to see a light directly behind her that takes an outline of the monster controlling her, which immediately gives him bad vibes. Even the audience watching it can feel the bad vibe pulse from "Marble", with several younger members getting goosebumps and the older ones feeling a sense of dread. Even Flurry Heart breaks into tears from the feeling.
When Flash, Cold, Grand, Misty, and Adagio meet with Sombra to discuss the Dominators, we learn the truth about them. It turns out that a "Soulink" is suppose to be a a mutual and agreed bond between a human and a duel spirit they share a strong bond with, allowing the two of them to share a body, like Yugi and Atem from the anime. But, some spirits have figured out a way to force a Soulink without approval from a human, and have full control over the body for themselves. This corruption of the Soulink is refered to as a "Dominate". It turns out that all the members of Team Dominator have been Dominated themselves, meaning they are trapped in their own bodies and suffering just like Marble is.
It turns out that the Dominators have been possessed for over a year, ever since the Shadow Gates incident when the Duelists of the world called out to the spirits for help. We see one of these through a flashback. Scarvolt was heading through a tunnel of light, rushing to help her Duelist after hearing her call. But Scarvolt was attacked by another unseen spirit during this and was pushed back by the evil spirit, blacking out while worrying about her partner. When she woke up the incident was over, but her link with Tempest was gone, due to the spirit that had Dominated her.
We see brief glimpses for the pasts of each of the spirits controlling the Dominators throughout the second round. Though most of the details are unclear, it is clear that death and destruction were heavily involved in their pasts, with them suffering from it.
During the finals between Team Dominator and Team V-Fighters, when Spike is about to win against Hellfire, Hellfire suffers another panic attack over losing to a human and has another vision from his past, where he sees his old home in ruins and hundreds of dead bodies littering the area around him. Then he spots his own dead body, and believes he is seeing his future. As he continues to panic, Victory Ace's attack completely consumes him, despite his attempts to resist it, before he is brought back to reality.
Hellfire: No, no. This can't be my future. (raises his arms to try to fight against Victory's Ace's attack, but is overwhelmed by it) Please...don't do this. Please no. I don't wanna...I don't wanna DIE!
Despite the spirit possessing Starlight going through a massive Villainous Breakdown over the course of several chapters, when Sunburst finally beats her and Starlight is set free, the spirit is almost disturbingly calm about it. Instead of yelling and shouting as Starlight is freed, it simply warns her that they will see each other again.
After Trixie's team was eliminated in the Double X, she was approached by "Starlight" who offered her a chance to make her every wish come true. The next time we see Trixie, she is being held prisoner in an unknown location. Apparently, Trixie accepted the deal, but quickly regretted it since everything immediately went downhill for her, kidnapped and separated from her friends. When a pair of figures come to get her from her prison she is completely terrified, and by the end of the story she has been Dominated herself.
Yugioh EQG: Ω Zenith
In a series where each story slowly gets Darker and Edgier with each entry, how does this, the final story in the series begin? With Thorax being defeated by one of the Omega Zealots and shortly afterwards a building blowing up. This is then topped by the end of the chapter when Flash, the main character, is beaten by one of them too and imprisoned.
The Zenith Dragons are all this. All of them were created by Zeronull, and each is used by one of the Omega Zealots. Not only are they each individually strong monsters, when played they become real and do real damage to the surrounding area. The ARC System has nothing on them.
Anyone beaten by an Omega Zealot gets automatically sent to Void, an empty space between dimensions, which the Zealots made into a prison for their own purposes. There, the defeated candidates are slowly corrupted for one of them to become the vessel for Zeronull.
When Soarin sees the Wind Zenith Dragon, Marventus, he quickly rushes to where it was, seeing it was where Wonderbolt Academy was, and that Rainbow and his other friends could be in danger. When he gets there though, it is too late and the academy is completely destroyed, with Rainbow buried in the rubble. Though lucky he manages to pull her out and get her help.
The Zealots show they have the ability to make cards explode on command, essentially turning them into miniature bombs. Glorianna uses this ability to force Twilight to duel her by threatening to detonate several at once in an airport, and Hellfire uses them to attack Spike and Thorax.
When Spike meets with the other defeated candidates (and Scootaloo) in Void and sees them dueling each other to pass the time, they explain it is all they can do since they already looked everywhere for an exit. Spike points out they probably did not look very hard since Twilight was only there for an hour before he was. This shocks the others, since there are no clocks or windows there, meaning they can't tell how long it has been. Though this is played for laughs it implies that everyone is slowly starting to Go Mad from the Isolation, and that this just makes the process they are going through happen that much quicker.
While Cold Steel is examining the Fire Zenith Dragon card they acquired after Sunburst defeated Hellfire, he feels as if the card is staring back at him and was screaming at him to let him fight. Cold actually notes it makes since for the monsters created by Zeronull to be battle hungry.
Draconequus reveals that he was given a special power by Zeronull to use against their enemies, but It Only Works Once. When he duels Cold Steel, he uses this power, revealing that he placed a curse on Cold that will drain his life force each time he loses life points, and if Cold's life points reach zero he will die. Cold is put in intense pain just from losing a mere 100 life points at the start of the duel, and he gets in such bad condition he is unable to continue the duel himself and requires Flash to step in and help him.
After Draconequus is defeated by Cold and Flash, before Discord is freed from his control, rather than have a Villainous Breakdown over his fate he simply tells the two of them that even without him around they won't be able to stop Zeronull's return.
The ending of chapter 19. Despite all their efforts, Twilight and Spike are defeated by Lady Marble and Ouravas, with Lady Marble using two Zenith Dragons against them at once, completely destroying the building they were dueling on top of. Then things go From Bad to Worse, when Twilight is made Zeronull's vessel.