The time-traveling dragon devouring the souls of the dead is all Alduin, the Eater of Worlds, who goes into battle with the player twice in The Elder Scrolls V: Skyrim. In both cases, you will need to learn the powerful shout "Dragon Slayer", which will knock the dragon to the ground, so that you can fight with him in close combat (you need to use the shout, even if you prefer ranged weapons). The battle strategy is approximately the same in each case, but in the final encounter you will face several additional restrictions due to the fact that the action will take place in Sovngarde.
Steps
Method 1 of 2: Battle at the Throat of the World

Step 1. Prepare to climb the mountain
Buy or prepare several health and fire resistance potions in any city. Consider hiring a companion to help you.
- Melee fighters like Lydia or Mjol are good at tanking to attack Alduin when he lands. Illia will also become a reliable partner, as she is good at ice spells of the school of destruction.
- On your way to the top, you will encounter several ice ghosts, so you shouldn't be hurt by a couple of cold resistance potions.
- If you pumped the spells of the school of restoration, you can use them instead of potions of health and resistance.

Step 2. Learn the shout "Dragon Slayer"
When you reach the top of the mountain, you will talk to Paarthurnax and watch a long cutscene to learn how to shout before fighting Alduin.
Paarthurnax will help you in the battle with Alduin by distracting his attention, but you will have to take most of the damage yourself

Step 3. Use the Dragon Slayer to knock Alduin to the ground
Press and hold the shout key to attack. Watch Alduin's flight with the help of the in-game camera while the scream is active so as not to miss. If you miss, you will have to wait for the shout to recharge.
- Equip the Talos Amulet to reduce the cooldown of your shout.
- Paarthurnax will fight Alduin in the air, but Alduin cannot be damaged until you knock him to the ground with Dragon Slayer.
- If you press and immediately release the key to which the shout is attached, your character will utter only one syllable of the shout, which can effectively stun Alduin on the ground. You can use this attack to prevent the dragon from flying up again.

Step 4. Use the shout "Clear sky"
Alduin has his own screams that rain down a meteor shower on the ground. If this happens, you can stop the Dragon Shout from Clear Sky.
- You will be taught this cry by the Greybeards before you are allowed to climb the mountain, so you shouldn't miss this skill.
- If the shout is still on cooldown, then it's time to drink a potion of fire resistance.
- Remember, when you use the Clear Sky shout, your shouting ability will need to be restored before you can use Dragon Slayer again.

Step 5. Try not to approach Alduin from the front
As soon as Alduin is on the ground, he attacks with fire breath, which deals a lot of damage to everyone in front of the mouth, as well as powerful tail blows from behind. Try to attack the dragon from the sides, whatever your combat style (ranged / melee).
- Eventually the dragon will turn to bite you (you will be in front of the mouth again), so keep moving sideways.
- Fire resistance potions will help you if you want to attack from the front, but it's best to avoid it anyway.

Step 6. Use ice spells
If you pumped the branch of spells of the school of destruction, then such spells (for example, Ice Thorn, Ice Storm) will inflict more damage on Alduin, since he has a slight vulnerability to cold.
- The Ice Storm spell can harm your companion, so use it carefully.
- If you know the "Death Sentence" shout, it will significantly increase the damage from your spells, but it will not be so easy to calculate the time so that you can use three shouts at once.

Step 7. Apply poison to the weapon
Slow Poison is as effective against Alduin as it is against other undead. Such a poison can be made or bought at an alchemist's shop in any city.
Poisons are very effective if you attack with arrows from afar while your companion distracts Alduin in melee combat

Step 8. Do not slacken the onslaught
Keep Alduin on the ground with the help of Dragon Breaker, drink health potions as needed, and soon Alduin will have to retreat.
Method 2 of 2: Battle of Sovngarde

Step 1. Prepare for battle
If you've already entered Sovngarde, you won't be able to return, so you'd better have enough health and fire resistance potions with you. Try wearing armor that increases fire resistance, and a weapon that would heal you on hit (like the Ebony Blade or something else with a health absorption enchantment) if you have one in your inventory.
- The point of no return in the storyline is when you decide to travel to Skuldafn from Whiterun. You will lose all the progress you earned in the dungeon if you want to go back to the previous save and shop in the city.
- If you pumped the line of spells of the school of restoration, you can replace potions of health and resistance with these spells.
- It is impossible to transfer to Sovngarde with companions without the appropriate mods, but you can get help from local NPC characters.

Step 2. Use the shout "Clear sky" three times
Your NPC companions will automatically use the same shout when you start clearing Alduin's mist. The dragon will fog up until you shout “Clear Sky” three times.

Step 3. Use the Dragon Slayer to knock Alduin to the ground
Press and hold the shout key to attack. Watch Alduin's flight with the help of the in-game camera while the scream is active so as not to miss. If you miss, you will have to wait for the shout to recharge.
- Equip the Talos Amulet to reduce the cooldown of your shout.
- Although NPC characters will attack Alduin in flight, he cannot be damaged until you force him to land with a shout.
- If you press and immediately release the key to which the shout is attached, your character will utter only one syllable of the shout, which can effectively stun Alduin on the ground.

Step 4. Let your allies take the damage
Whenever alduin lands, wait a few seconds for allies to attack him and get his attention.

Step 5. Do not approach the alduin from the front
As soon as Alduin is on the ground, he attacks with fire breath, which deals a lot of damage to everyone in front of the mouth, as well as powerful tail blows from behind. Try to attack the dragon from the sides, whatever your combat style (ranged / melee).
- Eventually the dragon will turn to bite you (you will be in front of the mouth again), so keep moving sideways.
- Fire resistance potions will help you if you want to attack from the front, but it's best to avoid it anyway.
- If you have to choose, it's better to get hit by the tail than to get caught in a stream of fire. The damage will be significantly less.

Step 6. Use ice spells
If you pumped the branch of spells of the school of destruction, then such spells (for example, Ice Thorn, Ice Storm) will inflict more damage on Alduin, since he has a slight vulnerability to cold.
- The Ice Storm spell can harm your helpers, so use it carefully.
- If you know the "Death Sentence" shout, it will significantly increase your spell damage, but it is best to use Dragon Slayer often to keep Alduin on the ground.

Step 7. Apply poison to the weapon
Slow Poison is as effective against Alduin as it is against other undead.
Poisons are very effective if you attack with arrows from afar, while NPCs are attacking Alduin in melee

Step 8. Repeat these steps
Keep Alduin on the ground with the Dragon Breaker, let allies distract his attention so that you can heal if necessary. In the end, Alduin will weaken and be defeated forever.
Advice
- You may encounter Alduin as you explore the game world. He will fly from mound to mound, awakening other dragons. You can damage him, but you cannot kill.
- The Battle of Sovngarde is the final battle of the main storyline. If it seems to you that it will be difficult for you, and at the same time you do not want to go back to an earlier save, you can lower the difficulty level of the game in the settings (this can be done at any time).
- Alduin has high resistance to fire and vulnerability to cold.
Warnings
- Monitor your companion's health bar. Melee fighters (such as Lydia) can die from Alduin's fire breath.
- Skyrim has a lot of bugs. On rare occasions, Alduin can remain invulnerable throughout the fight. If this is your case, try restarting the game from the last save location. If you have the most recent version of the game, then this should not happen, and the game will automatically save right before the battle.