A. Dangerous. Path. WINS. In the Riverclan and Thunderclan battle, Graystripe calls to Fireheart. When Bluestar's children, Mistyfoot and Stonefur, are trying to kill her, Fireheart, even after being called a traitor by Bluestar, saves her life. Graystripe then warns Fireheart to look out as Graystripe's leader, Leopardstar is about to attack Fireheart. After being exiled and taken into Thunderclan, Fireheart asks, "So can Graystripe stay?".
Cloudtail telling Brightheart she is still beautiful to him.
Mistyfoot and Stonefur forgiving their mother:
Mistyfoot (to Bluestar while she's dying): "We forgive you, Bluestar."
Stonefur: "We forgive you."
Yellowfang's speech to Cinderpelt about losing someone in Forest of Secrets.
The New Prophecy
Throughout Sunset, Leafpool has been looking for Cinderpelt in StarClan but can't find her. Then Yellowfang shows her Cinderkit opening her eyes and she realizes Cinderpelt is Cinderkit.
Squirrelflight and Brambleclaw reconciling in Sunset.
Crowfeather: You walk in my dreams, Leafpool.
Power Of Three
In The Sight when Graystripe comes back all of the clans start cheering him on.
At the daylight gathering, Firestar announces one apprentice gets special mention: Jaypaw.
Half-Moon watching over Jayfeather from the afterlife in Long Shadows.
Pretty much every time new kits are born (except for maybe Silverstream's and Yellowfang's).
Naming ceremony at the end of Eclipse: "Cinderheart, you are a warrior at last".
Omen Of The Stars
In The Fourth Apprentice, when Honeyfern tells Jayfeather that she wants Berrynose and Poppyfrost to be happy together.
Tigerheart and Dovepaw in general.
In Night Whispers, Tigerheart stopping Ivypaw from destroying Flametail.
In Sign of the Moon, Dovepaw completely fails the first part of her hunting assessment. Then, during the second part, Icecloud falls into a hole and Dovepaw dives in to pull her out. Back at the camp, when Spiderleg and Lionblaze are reporting on Dovepaw's assessment, Spiderleg completely tears Dovepaw apart. Just when it looks like Dovepaw won't get to be a warrior, Spiderleg finishes his report by telling Firestar that no matter how horribly Dovepaw did at hunting, she showed true courage and selflessness by diving into the hole to save Icecloud, and that Firestar would be a fool not to make her a warrior.
That last line in Sign of the Moon, "I will wait for you forever, Jay's Wing!"
In The Forgotten Warrior, Cinderheart's memory montage as she remembers her old life as Cinderpelt.
Firestar telling Sandstorm how much he loves her in The Last Hopebefore he enters his final battle.
In The Last Hope, Bluestar's eulogy for Firestar.
Bluestar: "I gave him a life for nobility, though he was born with more nobility than any warrior I ever knew.
From the ending of The Last Hope:
Brambleclaw:"Will you be my deputy, Squirrelflight?"
Before the final battle in The Last Hope, Lionblaze, Hollyleaf, Jayfeather, and Brambleclaw forgive Leafpool and Squirrelflight, then apologize for how they'd been treating them since Sunrise. This is followed by Brambleclaw telling Lionblaze, Jayfeather, and Hollyleaf how proud he was to be their father.
During the final battle in The Last Hope, Hollyleaf sacrificing herself to save Ivypool. In the end, instead of seeking glory, she gave everything for a friend. Then she tells Leafpool that she's okay with dying, as she came to understand her mother.
In The Last Hope, Crowfeather reconciles with Lionblaze and Leafpool. D'awww.
Halfway through The Last Hope, the Three have given up, the Dark Forest is rising, and the Clans are awaiting the end of all things. Then Jayfeather gets his hope restored by Mothwing, when she shows him that there really is a way to save the Clans.
The ending of The Last Hope.
There will be three cats, kin of your kin, with the power of the stars in their paws. They will find a fourth, and the battle between light and dark will be won. A new leader will rise from the shadows of his death, and the Clans will survive beyond the memories of his memories. That is how it has always been, and how it always will be.
Crookedstar: "No, Mapleshade. I still have the cats that I loved. You have nothing and no one."
Crookedstar assured Silverkit that he wasn't really fighting with Oakheart.
Crookedstar: "It's okay, nobody's hurt. Don't be frightened. We're not really fighting. We're training, that's all. Everything's fine."
Silverkit: "You're really just training? Do you promise?"
Crookedstar: "I promise. I'm your father, Silverkit, and that means I will always keep my promises."
Oakheart's line to Bluefur in Bluestar's Prophecy, after he admitted to her that he couldn't stop thinking about her and she told him that he didn't even really know her: "I want to know you. Everything about you—your favorite fresh-kill, your earliest memory, what you dream of..." The line caught me off-guard and struck me as extremely romantic, so much that I gushed aloud.
Crookedstar discovering that he's going to be a father.
Crookedstar: I have to tell Oakheart. I have to tell everyone! *runs off but stops and faces Willowbreeze* It's okay, isn't it? If I tell everyone?
Crookedstar: *runs into camp* Willowbreeze is expecting kits!!
Thistleclaw seeing his newborn son for the first time and telling Snowfur that he's proud of her. It's especially touching because, well, this is Thistleclaw we're talking about.
For the first time ever, Bluefur felt almost fond of her sister's mate.
Mistyfoot being reunited with her kits at the end of her leader ceremony.
"Perchkit! My baby!"
When Brokenstar was a kit, he was helping Yellowfang (the former not knowing she's his mom) with some medicine supplies. And when he gets some leaves on top of him, he squeals "I'm a tree! I'm a tree!" This shows that indeed, every villain in the series starts out as a cute little kit.
Unfortunately, it's also a Tearjerker because he'll eventually lose this personality and become more cruel.
Everything about the ending of Tallstar's Revenge. Especially, "I give you this life for forgiveness. No death need ever be avenged. Forgiveness brings peace far more surely than vengeance." and Tallstar learning about Jake's son.
This exchange in Tallstar's Revenge.
Jake: "Will you go home now?"
Talltail: "I don't know if I have a home."
Jake: "Of course you do! You have WindClan!"
Talltail: "I left WindClan."
Jake: "They'd let you back."
Talltail: "I thought I'd keep travelling for a while. Would you like that?"
Jake: "I think you should go home."
Talltail: "Home? I have no home. I don't even know who I am anymore."
Jake: (Rests his muzzle on Talltail's head.) "I know who you are. You're my best friend, and you always will be.
Shrewclaw giving Tallstar one of his nine lives.
Shrewclaw:"I know we were never friends, Wormcat."
Talltail:"I'll be Wormstar now."
Shrewclaw:"But loyalty isn't rooted in friendship. It's much stronger than that. It comes from being born and raised under the same sky, from walking the same path as our ancestors, and from sharing the warrior code. With this life I commit you to upholding the warrior code, whatever challenges you might face. This is the wisdom of our ancestors, all our traditions distilled. Trust the code to lead you along the right path."
Stars swirled through Talltail's mind as the life pulsed through him. He and Shrewclaw were one. Not friends. But they would fight side by side in any battle.
The origin of Deadfoot's name in Tallstar's Revenge. It comes off as an Unfortunate Name in the first arc, but seeing him so unbelievably happy about it? That's perfect.
Talltail's selfless act helping RiverClan paying off in the end of Tallstar's Revenge when he saves Hopkit.