Dragon Rising

The Dragonborn's first battle against a dragon takes place during this quest, as well as their first absorbed Dragon Soul and the call of the Greybeards to High Hrothgar.

Background
A dragon has been sighted at a watchtower near Whiterun. Jarl Balgruuf sends his housecarl Irileth, as well as some soldiers and a newly arrived warrior to kill the dragon.

Walkthrough
Follow Irileth to the Western Watchtower, which was attacked by Mirmulnir. Many men from the Whiterun garrison accompany the Dragonborn and Irileth in battle with the Dragon, equipped with bows and swords.

Use the debris of the wrecked tower for cover, or climb to the tower's summit. From either location, use ranged weapons or spells to attack Mirmulnir. Once his health drops to below half, he should land, allowing melee attacks against him. Irileth and the guards may be able to distract Mirmulnir, long enough for a melee-oriented Dragonborn to attack from the flank or behind. Beware of his deadly breath.

Aftermath
After Mirmulnir is defeated, the player character absorbs his soul, much to the surprise and astonishment of the soldiers, who proclaim that they must be a legendary "Dragonborn." Irileth, who is skeptical about the theory, tells the Dragonborn to report back to the Jarl. On the way back, they hear a loud sound. Jarl Balgruuf explains it to be the Greybeards calling them to High Hrothgar, and explains what it means to be a Dragonborn.

After completion of this quest, Dragons will begin appearing in the wild and attacking the Dragonborn at random.

Rewards
The Jarl promotes the Dragonborn to Thane of Whiterun, gives them the Axe of Whiterun, and assigns Lydia as their housecarl.

Trivia

 * Waiting to complete this quest until later in the game can be useful to some players. The random dragon attacks can kill non-essential NPCs who still have favor activities or quests, make travel difficult, or simply annoy the player with the frequency of attacks.
 * Tor is only mentioned during this quest. He was picked up and eaten by the Dragon. Whiterun guard armor can be found on the Dragon's corpse, and it is most likely Tor's armor.
 * It's not necessary to wait for Jarl Balgruuf to make his speech before going to fight Mirmulnir. As soon as Irileth interrupts Farengar, go to the Western Watchtower, and a quest marker will already be there.
 * Before starting this quest, the Western Watchtower is an unmarked location and is already destroyed, but without the fire.

Bugs

 * Sometimes Lydia, the housecarl, does not appear and cannot be found. To fix this bug, open the console and type:
 * Sometimes after killing the Dragon, no dialogue is initiated and no shout is performed.
 * Sometimes when killing Mirmulnir, instead of saying Dragon Soul absorbed, it says that the first word of Unrelenting Force was learned.
 * Sometimes Irileth will not run into Dragonsreach with info on the dragon sighting, preventing the quest from starting. This only seems to happen when talking to Farengar about the Dragonstone BEFORE obtaining it. Obtaining the Dragonstone before the first visit to Dragonsreach prevents this problem, as all the essential NPCs are already inside Dragonsreach. It is unclear if the bug only occurs in modded games (including official DLCs), or whether it is actually a vanilla problem. If the quest does not start, even using the 'SetStage' console command will not help start it.
 * This quest has a chance of becoming bugged if done at a high level (15 or higher, when Mirmulnir spawns as a Blood Dragon). Mirmulnir will kill the guards in one attack and sometimes kill them faster then they respawn, resulting in no dialogue initiated when the Dragon dies.

Achievements
Дракон в небе (Квест)