Fievel tries to ward off the Cossacks' cats to protect his two sisters.
Tony instantly develops this for Fievel, trying to help the kid find his family and keeping him safe from any danger they encounter. Part of the reason why he used his slingshot on Warren was because he was demanding that the mice give him Fievel.
Tadashi in Big Hero 6 for his younger brother Hiro, against threats both physical (his rescue of Hiro from a bunch of Sore Loser bot fighters) and non ("Mr. Krei? That's my brother's" anyone?). Later on, the rest of Tadashi's friends, especially GoGo, look after Hiro after Tadashi dies.
Kenai hates bears and finds Koda REALLY annoying at first, but after some bonding and a lot of Character Development, he would still go through anything to protect him. In fact, Kenai and Koda were previously the page image for this trope.
He likely gets it from his own brothers. His oldest brother Sitka dies early on, protecting Kenai from the Mama Bear he angered. Then, Denahi (the middle brother) spends the movie in a misguided attempt to kill Kenai in bear form, mistakenly thinking that bear-Kenai killed human-Kenai.
This carries over into the sequel, where Kenai risks storming into a village and fighting off the residents to protect Koda, who's been run up a tree by the villagers.
A Bug's Life: While he's not related to her, Flik is quite protective and caring toward Dot. He's the only one who steps in to stop Hopper from terrorizing Dot in the beginning, and he gives her a motivational speech about how she can do amazing things despite being so small.
After Anna informs Elsa about the Endless Winter, Elsa panics and accidentally shoots Anna in the heart. Worrying Anna isn't safe near her, she conjures a giant snowlem to throw Anna out of her ice palace, believing this will help protect her.
The film also gives an inversion with the same pair. Anna is quick to speak in defense of Elsa when Elsa freezes the kingdom and it appears as if it was on purpose, is the one to insist saving both Elsa and the kingdom is possible and sets out alone on a quest to do just that, and at the climax, she makes a Heroic Sacrifice by jumping in between Elsa and Hans's sword. When she turns out to be alright, Anna's only explanation for why she did it is that she loves Elsa, and the tone she says it in makes it sound like something Elsa should've expected rather than be surprised about.
Fly in Help! I'm a Fish, who's pretty caring when it comes to Stella, his little sister. Case in point: When it seems like searching for her in starfish-form in the ocean via boat is hopeless, he doesn't hesitate to drink a potentially dangerous potion and dive in, in order to continue searching.
Violet fully reciprocates. To specify, her Big Sister Instinct goes as far as throwing herself between Dash and multiple machine guns. Her dialogue when Dash asks how she managed to throw up a ball-shaped shield that covers both of them all but states that she fully intended to dieTaking the Bullet for him.
Both Violet and Dash become incredibly protective of their baby brother Jack-Jack in the sequel. When they're on a mission to save their parents and foil the plans of the movie's villain, they make it a priority to keep Jack-Jack safe from all the Screen-Slaved supers.
In Joseph: King of Dreams (a Prequel to The Prince of Egypt), Joseph's many older brothers plan on having this when their baby brother is born. Unfortunately, a whole lot of Parental Favoritism sours that, leading them to sell Joseph into slavery in Egypt and tell their father he was killed by a wolf. At the end of the movie, it's revealed that the brothers feel immense guilt over what they did and are very protective of Benjamin, to the point where, when Joseph tries to arrest Benjamin for a crime that wasn't committed, all of the brothers offer themselves up in his place. This moves Joseph enough to forgive them all.
In Oliver & Company, Dodger initially wanted nothing to do with Oliver but after accidentally getting Oliver involved in the gang's troubles with Sykes, he starts to consider Oliver his responsibility and looks after the little kitten, considering Oliver as much as a member of the gang as the other dogs.
Eventually Courtney of Paranorman gets to be this way, to the point where she'll throw herself between an oncoming mob and her little brother.
Ramesses's first reaction to his little brother killing a man in front of multiple witnesses is to declare him innocent. When Moses returns after years of being gone he is ready to give his brother a high position and wipe away the crime. That doesn't work out.
There's also Moses's biological brother Aaron, who tries to protect Miriam when they first encounter Moses, who at this point is still considered Egyptian royalty and therefore a threat to them.
Miriam herself goes into protective big-sister mode with Moses: Right at the beginning of the film when she follows baby Moses' basket down the Nile, and then later when she steps in to save Moses, who is no longer a royal and is about to be the focus of a No-Holds-Barred Beatdown at the hands of mob of angry Hebrews led by Aaron.
Ratatouille: Rémy realizes Émile is about to get caught in a trap set by Skinner, and saves him, causing himself to be caught in the trap. Émile immediately rushes off to get Django to set Rémy free.
Jack Frost in Rise of the Guardians acts much like an older brother to all the children around him. It makes sense as what led to him becoming a guardian was him sacrificing himself to save his little sister from drowning.
Robin Hood (1973) has the titular character acting this towards Skippy and the other children. After the Sherif takes Skippy's birthday present (a gold coin his family saved for him), Robin comes in to cheer Skippy up and gives him a bow and arrow and his hat. Later on, when one of Skippy's sisters struggles to catch up with the escaping villagers from Prince John's castle, Robin doubles back to get her.
Strange Magic: Marianne, whose instinct is strong enough that she's willing to single-handily storm the castle of the Bog King to rescue her kidnapped sister. It's only after Marianne grudgingly acknowledges that the Bog King has been a perfect gentlemantis to her sister does Marianne warm up toward him.
The Super Mario Bros. Movie: Mario to Luigi, in spades. His whole motivation upon landing in the Mushroom Kingdom is saving Luigi from Bowser. It's even showcased in the opening scene with Foreman Spike, where the one thing that makes Mario visibly upset isn't Spike mocking Mario or his ambition of starting his own business, but Spike talking shit about his little brother by calling Luigi an idiot.
In Toy Story 3, Andy is a kind brother to his sister, Molly, despite their light bickerings. When she had trouble lifting a box, he immediately went to help her. And at the end, with Bonnie, who is a Shrinking Violet. He kneels down at eye-level to her, introduces all his toys to her, and played with all his toys one last time with Bonnie before he left.
Scowler from the Walking with Dinosaurs movie eventually does this. When he sees Patchi return after kicking him out of the herd, he quickly warns him to keep away from the attacking Gorgosaurus and get to safety.
Wreck-It Ralph: The title character is this towards Vanellope. At first he wants nothing to do with her, especially after she steals a medal that he believes will earn him the respect of those he works with. As the two spend time with each other, and seeing they are surprisingly similar, Ralph becomes protective of her.
Chuck in The Angry Birds Movie 2 is very protective of his little sister, Silver, to the point of threatening to break every bone in Red's body if he tries anything and reacting with suspicion anytime he finds the two together. By the end of the movie, he chills out a bit.
