Aslan is the only character who is in all seven of the Chronicles of Narnia. He is the creator of Narnia and the Son of the Emperor Beyond-the-Sea. He is said to have nine names although they are not all mentioned in the Chronicles. He has the ability to appear in forms other than a lion: an albatross, a lamb, and a cat.
The Magician’s Nephew
Aslan creates Narnia by singing it into existence. He also creates animals and creatures and gives some of them the ability to speak and reason. This is witnessed by Digory, Polly, Uncle Andrew, Jadis, The Cabbie, and Strawberry (The Cabbie’s horse).
Aslan declares The Cabbie to be the first king of Narnia, and calls his wife into Narnia to be the first Queen of Narnia.
Aslan orders Digory to fetch an apple from a garden beyond the western mountains so it can be planted to keep Jadis out of Narnia. Digory does so with the help of Polly and Strawberry, who Aslan allowed to go with him. When they return Aslan tells Digory to plant the apple. It quickly grows into a large apple tree. Aslan allows Digory to take an apple from the tree back home to his mother with the promise that it will cure her from her illness.
Aslan then sends Digory, Polly, and Uncle Andrew back to our world, where they find that no time has passed since they left.
The Lion, the Witch, and the Wardrobe
Aslan’s return breaks the power of the spell cast by Jadis (now known as the White Witch), and spring begins to arrive.
Edmund betrays his siblings to the Witch Witch. They escape with the help of Mr. and Mrs. Beaver and go to meet Aslan at the Stone Table. After He greets them, He then inquires where Edmund is. They tell Him that he betrayed them and ask if anything can be done to save him. Aslan replies that "All shall be done, but it maybe harder than you think."
After Edmund is rescued, the White Witch demands his blood in order to fulfill the requirements of the Deep Magic concerning traitors. Aslan speaks with her privately and afterwards she renounces her claim on Edmund’s life.
Aslan tells the others that they must move the camp to another location because the Stone Table will be needed for other purposes. They do so.
That night He slips away from the camp and returns to the Stone Table, where the White Witch and her minions are waiting for Him. He willingly offers His life in exchange for Edmund’s. Susan and Lucy, who had followed Him there, witness this and are heartbroken.
He comes back to life at dawn the next morning, and then travels with Susan and Lucy to the White Witch’s home to free the stone creatures, which will be needed to defeat the White Witch’s army.
At the battle, he defeats the White Witch and afterward, with Lucy’s assistance, restores the wounded troops.
He establishes the four Pevensies as Kings and Queens of Narnia, and slips quietly away afterwards.
The Horse and His Boy
Unbeknownst to Shasta, Aslan is present with him throughout his whole journey. He is the lion who forces him to join up with Aravis, He is the cat who comforts Shasta at the tombs, and He is the lion that chases them to the hermit’s house so that they could warn King Lune in time.
Shasta first meets Aslan when he is riding through the fog. Aslan tells him everything mentioned above.
Aslan appears to Bree, Hwin, and Aravis at the hermit’s home. He welcomes Hwin, rebukes Bree’s pride, and tells Aravis why He clawed her back.
He appears one last time at the council where they are trying to decide what to with Prince Rabadash. Rabadash rails at Him, insulting Him, and Aslan turns him into a donkey. He tells Rabadash how he can be turned back into a human, and then disappears.
Aslan is first seen by Lucy at the edge of the gorge when they are traveling to join Caspian’s army at Aslan’s How. Peter, Susan, Edmund and Trumpkin do not see Him and decide to go down the gorge, despite Lucy declaring that Aslan wanted them to go up the gorge.
He appears to Lucy that night and tells her to wake the others and follow Him; if they refuse, she is to come alone. They reluctantly follow, even though Lucy is the only one to see Him at first. One by one, they all come to see Him before they reach the How.
After Aslan orders Peter, Edmund and Trumpkin to go help Caspian at the How, He summons the trees, Bacchus, and Silinus. After a merry romp, Aslan leads them all through the town, freeing the animals and any Telmarines who wish to join with them. He frees the River God by destroying the Bridge of Beruna, also cutting off the Telmarine army’s escape route.
After the battle is over, He declares Caspian King of Narnia.
Three days later, He makes a door in the air as a portal to send any Telmarines who wish to go to another world.
The four Pevensies, setting the example for the Telmarines, go through the door and find themselves back in England.
The Voyage of the Dawn Treader
Aslan first appears in the book on Dragon Island when He ‘undragons’ Eustace, which is not only a physical transformation, but a spiritual one as well.
He appears momentarily on the island of Deathwater to stop a quarrel between Caspian and Edmund.
He appears to Lucy on the Dufflepud Island and scolds her gently for using magic to eavesdrop on her friends. He introduces her to Coriakin, and then departs to visit Trumpkin at Cair Paravel.
In the form of an albatross, He leads them out of the darkness surrounding the island where dreams come true. He also destroys the island.
When Caspian declares his intentions of never returning to Narnia, but instead going to the end of the world, Aslan speaks to him and tells him that he is to return to Narnia at once and that Edmund, Lucy, Eustace, and Reepicheep are to go on to the end of the world.
Aslan appears, one last time, in the form of a lamb, to Edmund, Lucy, and Eustace. While talking to them, He changes to the form of a lion and tells Edmund and Lucy that they will never return to Narnia because they are too old. He tells them that He is in our world as well and then sends them all back to England through a door in the sky.
The Silver Chair
Eustace falls off a cliff in Aslan’s country while trying to save Jill and Aslan saves him by blowing him into Narnia. He (Aslan) then tells Jill that He called both of them into Narnia to find Prince Rilian, who has been missing for 10 years. He gives her four signs to help her find him and then blows her into Narnia as well.
He appears to Jill, in a dream, while she is at Harfang, the city of the giants. He asks her to recite the signs, and when she cannot do it correctly, He takes her to the bedroom window and shows her the third sign.
He appears to Eustace and Jill when they are back at Cair Paravel. King Caspian has just died and everyone has begun to mourn. The children ask if they can go home now and suddenly they are back on the mountain with Aslan, Caspian’s body is there as well. Aslan tells Eustace to drive a thorn into His paw, the blood drips onto Caspian’s body, bringing him back to life!
Aslan tell Eustace and Jill that it is time for them to return to England, Caspian asks if he might be allowed to see one glimpse of our world. Aslan says yes, and then tells him what will be happening at the moment Eustace and Jill return (the school bullies chasing them). He tells Eustace and Caspian to use the flats of their swords on the bullies, and He gives Jill a riding crop to use on the bullies as well.
He then roars loudly, knocking down part of the stone wall surrounding the school; Eustace, Caspian, and Jill quickly defeat the bullies. Aslan repairs the stone wall, and then He and Caspian return to Aslan’s country.
The Last Battle
Aslan first appears to the seven friends of Narnia and Tirian inside the stable, and welcomes them to His country.
He then declares that it is ‘Time’ and brings the world of Narnia (the ‘shadowland’ of the real Narnia, which is in His country) to an end. All of the creatures who both fear and love Him are allowed to come into His country, the creatures who both fear and hate Him are destroyed with Narnia.
When Lucy tells Him that they are afraid that He will send them back to England, He informs them that they have died in our world and that they can stay in His country forever.