How to defeat Alduin in The Elder Scrolls V: Skyrim

[Akshey]

A lot has been said about Alduin, his relationship to his Cyrodiilic counterpart Akatosh or Aldmer counterpart Auri-El. He has a hunger to swallow the world, but fortunately Dovahkiin is around to put him and his dragons/Jills back in their place. But how exactly? Dragons can be brought down in conventional combat, but Alduin is a god, and likely the end boss of the Main Quest. In Morrowind, we had to gather three MacGuffins - Wraithguard, Sunder and Keening - and face down Dagoth Ur both in single combat then destroy the Heart to end Second Numidium.

[Irene-I]

I don't have a clue, definitely something to do with the shouts and the greybeards, seems you need to master the shout power before you stand any chance and the greys are integral to that training. Also don't the dragons fear the dragonborn because he can absorb them and use their power, it must be something to do with Alduin can only be killed (or banished since I don't think you can kill a god literally) by essentially his own power.

[DougWison]

Be awesome if there's some really powerful shout that can destroy him but it's very, very long, like a large paragraph. You can't kill him by physical harm, magic or normal shouts so the battle is just to wear him down so you have time to execute this powerful shout, so you got your buddy dragon scrapping with Alduin, perhaps some greybeards using shouts against him and buffing your buddy dragon while you’re standing on the highest point of high hrothgar doing this massive chant with all of Skyrim laid out before you. Alduin is desperately trying to claw his way up to stop you shouting, a massive storm is raging from the power of the shout while the factions army you help is fighting a group of jiil dragons and slowly losing, everything coming down to whether you can pull off this shout in time, sounds epic to the music I'm listening to right now.

[Ashley Parker]

The solution is simple yet epic: You get a dragon shout which forces all mudcrabs of tamriel under your command and together you stop Alduin. He will just drown under the giant army and suffocate.