Odahviing

Odahviing was an ally of and right-hand dragon to Alduin, the main antagonist of The Elder Scrolls V: Skyrim, now ally to the Dovahkiin after he was captured (and freed) at Dragonsreach. He then thanks the Dragonborn by siding with them in the war against the World-Eater, ready to fight back against him for the unforgivable acts he has caused.

Role
For a long time he and his kin had disappeared from the face of Nirn, he was thought to have been killed and buried somewhere southeast of Rifted. However, that all changed when Alduin appears in Helgen and leaves the village in a singed ruin. From there, he resurrected much of his fallen allies, Odaviing being among them. He is not mentioned or shown until near the end of the main storyline. The Dragonborn is instructed by the Blades leader Esbern to capture him using the trap set up in Dragonsreach in Whiterun. After speaking with the Jarl, they reluctantly agree to use the trap as a means to end the Dragon War as soon as possible. The Dragonborn uses a unique shout to lure Odaviing towards the keep, and after a fierce battle, he becomes trapped.

From here, Odaviing is dumbfounded by the Dragonborn managing to trap them, but also acclaims them for the strategy. He makes them the offer of leading the Dovahkiin towards where Alduin is hiding out, an ancient Nordic temple called Skuldafn, which houses a portal to Sovngarde, the Nordic afterlife. The Dragonborn agrees and in the process, Odaviing also pledges loyalty to them for their actions, before finally leading them to the temple.

After the Dragonborn manages to slay Alduin a second and final time, he/she returns to the Throat of the World, where Odaviing and the rest of the dragons redeem themselves and pledge full loyalty towards the Dovahkiin for their impossible feat. After they leave, Odaviing makes his last act of redemption by allowing the Dragonborn to use his shout as a means to call in for assistance.