Warning: Spoilers Off applies to this page. Proceed at your own risk.
Hope of the Shield Hero
Naofumi busting out the Shield of Hope and destroying Motoyasu's armor with Hope Asunder.
To his credit, this Motoyasu proved he is capable of actually being a decent challenge to Naofumi, where his canon counterpart never did.
Itsuki calling nobles out on their corruption and abuse of demihumans.
The duel between Naofumi and Malty. It's obvious that, had Malty not been outrageously cheating, Naofumi would have clearly won.
To Malty's credit, she proves more of a Worthy Opponent to Naofumi than you'd expect a Spoiled Brat like her to be. Being able overwhelm him and not fall for his tricks she's seen before. Compare to canon, where Malty Can't Catch Up to Naofumi even with a major level advantage.
Itsuki, Naofumi, and Ren having a sit-down after arriving at Van Reichnotts' manor: where the three of them learn about the Sword and Bow's Power-Up Methods and start going through their Legendary Weapons' upgrade systems to become that much stronger together.
Itsuki, Naofumi, and Ren working together to kill the Tyrant Dragon Rex that Idol Rabier summons — the same that required Fitoria to actually finish off in canon; a beast so powerful that a previous set of Four Cardinal Heroes in the past saw no other option but to seal it away.
Naofumi managing to find Bitch’s Berserk Button and relentlessly pressing it until she proceeds to explode in a furious tirade where she reveals how her desire for power would drive her to kill anyone in her way…including Motoyasu, who hears every word of her confession. This directly plays a part in Motoyasu finally pulling a Heel–Face Turn and fighting alongside Naofumi against Pope Balamus.
The Four Cardinal Heroes fighting together for the first time to defeat Balamus.
Ren fighting off Glass, with Wyndia's support, while protecting a downed Naofumi.
Naofumi forcing Jaralis to back off when the demi-human attempts to call his bluff of taking control of Siltvelt's army and getting the entire Council executed.
Diligence of the Shield Hero
Naofumi, Ren and their parties stopping Itsuki while he's deep into the Cursed Series.
When Glass returns during the Cal Mira Wave, she's as powerful as ever - but the Three Heroes are a lot stronger than they were during the Third Wave. Naofumi uses the Soul Eater Shield to drain her, then combines two shields to protect the other Heroes from her attacks, and finally him and Itsuki use two spells to buff Ren and debuff Glass - and Ren casts One Thousand Swords, which completely overwhelms Glass' defenses.
Glass turns out to have an equivalent to the Cursed Series, similar to Naofumi's Shield of Wrath, but L'Arc and Therese manage to convince her to back down just by speaking to her.
When the Three Heroes Church's remnants attack Lurolona, Motoyasu leads the defense of the town, and the defenders manage to win in battle even though they were outnumbered - with Motoyasu proving that, while he may be the weakest of the Cardinal Heroes, he is very much a One-Man Army when he plays to his strengths, and the Filolials showing that they are Badass Adorable supreme.
Then, when one of the Queen's Shadows manages to track where the traitors have been hiding away, Motoyasu takes a small army and successfully attacks the mansion, taking out the traitors' main hideaway. Motoyasu single-handedly beats the strongest Church Shadows, making good use of the training he's undergone with Granny. And when it turns out that Bitch has escaped and left a trap behind, he manages to survive that as well.
The second battle against the Spirit Tortoise, where the heroes, their parties and all of Melromarc pulls out all the stops to kill the gigantic monster.
Filo returns, and becomes providential in allowing the close quarters fighters to approach the Tortoise, as she literally stomps on or runs over all its familiars.
Naofumi, Aksel and Bakta manage to halt the Spirit Tortoise by grabbing its foot and forcing it into the ground.
Everyone's combined efforts manages to hurt the Tortoise so much that it can't regenerate fast enough.
Filo shows that her time with Fitoria was not spent dawdling, and pulls off Wind Cutter, which opens a huge gash into the monster's neck.
When the Tortoise begins to gather energy for its ultimate attack, Naofumi has another panic attack and locks up. His mental representation of Wrath, in the form of himself under the Wrath Shield's influence, appears to browbeat him into accepting it as part of himself - only for Naofumi to instantly accept that his anger is part of him, but that right now his fear of failing his friends supersedes it. Wrath!Naofumi leaves, but not before implying that Naofumi can unlock another Blessed Series Shield, Diligence.
Just then, the Tortoise's ultimate attack hits - and Naofumi, using only the Shield of Hope II and with support of healing magic from the others, tanks the entire thing even as it makes him scream in blinding pain burns him up (to the point one of his eyes bursts) before the thank you gift from the Cal Mira Accessory Merchantdeflects the rest into a faraway mountain that instantly disintegrates. Naofumi immediately collapses, almost dead, but he saved the entire army from being killed by taking on an attack that is incredibly more powerful than Judgement.
Cursed!Ren vs Wyndia and Eclair.
The second fight against the Spirit Tortoise.
Ren saying "You lied to me." Right before cutting off the Book Hero's arm.
The Great Escape from the prison by Raphtalia's group. Raphtalia uses her powers of illusion to sneak out of the jail without being noticed, steals the keys while spooking the guards and frees the others. And she's doing this even though she's been returned to level 1 and is a child again.
The moment Kizuna flexed on Trash and his harem by instantly killing many of his Tiger Clones with one skill at the same time.
Raphtalia hits Trash with a skill and sheathes her sword, confident in victory. When Trash tries to move, it turns out that the skill has cut him in half vertically, so finely he didn't even realize until then, causing him to die a very painful (and messy) death.
Naofumi, Raphtalia, Filo, Dou-Lon, Itsuki, Rishia, Aksel, and Maya are fighting Kyo, but nothing they do manages to make a permanent dent on Kyo, who has transformed into a demonic dragon in his madness. Not even Itsuki using Bull of Phalaris has managed to stop Kyo. Naofumi is desperate enough to start to switch to the Shield of Wrath III, but then Filo begins to sing a song that starts to hurt Kyo and pushes back Naofumi's anger. Then Raphtalia points out that Kyo is exactly what Naofumi would become if something happened to her or Filo... and Naofumi has the epiphany he needs to fully accept his Wrath and completely embrace his place as a savior of worlds. Naofumi's Wrath doppleganger encourages him for finally getting it, and disappears, allowing Naofumi to unlock the Shield of Hope's true form, the Shield of Diligence. This not only allows him to heal everyone, but gives them a great boost to their power, and wield the Shield of Wrath for half an hour without suffering its drawbacks. With everyone back on their feet, their health restored, the group sets out to put an end to Kyo's madness and save him from himself, while Filo starts to sing again, happy that her parents are full sync.
Naofumi and Raphtalia's determination to end Kyo's madness inspires Aksel and Rishia to keep moving in order to protect their loved ones - which leads to them being chosen to become the Vassal Heroes of the Axe and the Projectile. And, seeing this, Hoshi and Akane also join in the fight, using their skills to distract Kyo while the others continue attacking. Even Daitan manages to find a way to help... by going completelynaked and tauntingKyo to give openings to everyone else and help Naofumi with his counterattacks. It works.
Naofumi realizes how they can finally win the fight, and leads everyone in crippling Kyo enough that he can trap him in True Pandora's Box, ending the fight.
Lapis's home fleet, led by Hinoka (Corrin's wife), does a Big Damn Heroes entrance by attacking the Wave monsters and Luvar's army, turning the tables in favor of the heroes.
Kyo, after finally going through his Heel Realization and deciding to go out on his own terms, reveals to Naofumi through his diary that he found information on "Them", the entities that reincarnated him in Kizuna's World in order to ruin it, even though they were constantly watching him, and preserved it, which should allow the Heroes to find a way to stop their plotting and save all the worlds.
He also leaves them a lot of information on ways to improve themselves, granting them new ways to become stronger and ready to stop the threat to all the worlds.
After the fight, Naofumi and Itsuki's parties remain for an extra week because they have to deal with the aftermath of the fight, as well as stop the reincarnators that were tasked by "Them" with destroying the world. The plan they make is simple yet very, very satisfying: gather all of them in the same room, cover all exits with the heroes and their parties, and proceed to waste them all, because the power and skill gap between the heroes and the reincarnators is too big to surpass even when they are outnumbered by more than ten-to-one. Even the strongest reincarnators, the ones with stolen Hero Weapons, are just barely able to hold on, and that's because there are too many targets.
One of the reincarnators manages to steal Kizuna's Weapon... because she allows it. When the guy tries to use it against Kizuna, it completely fails because it can't hurt people, as Kizuna cheerfully reminds him - and then, since she's now not restricted on what she can do, she uses her far greater power to turn him into Ludicrous Gibs with one punch.
Not even killing themselves (to take advantage of their Resurrective Immortality) is enough to escape, because the Heroes have Soul Eater weapons at their disposal, meaning that they get Killed Off for Real.
And Kizuna finishes it by making the false Harpoon Hero her messenger to "Them", telling the abominations that the Heroes will, sooner or later, go after them, and then putting the fear of all gods and demons in the world into the reincarnator so he will never forget the massacre and never find a moment of peace before they just finish him off forever.
After the reincarnators' massacre, Corrin lays down the law: if any of the countries represented there doesn't join the alliance against the Waves and "Them", then Corrin has no problem with that - but no one in the alliance will provide any help to them.
