Azir is the first champion to have his first ability point restricted to a single one (Arise!) since it's required for the other two (Conquering Sands and Shifting Sands) to function.
He is also the second champion to be unable to rank up a basic ability at Level 1, the first being Zilean.
Shurima's Legacy may be referencing the Egyptian solar disc god Aten (depicted as a sphere emanating rays of light each ending with a hand) and titular god of the short-lived monotheistic religion imposed by Pharaoh Akhenaten. His son Tutankhamun later restored the polytheistic religion.
One of the earliest Azir skillsets Colt 'Ezreal' Hallam worked on had an ultimate called 'Sand Hands' in which a pair of those would rise from the ground and, after a delay, move together pushing everyone between each other and squish them in.
Other themes included Sand Golem, Man with Sand Cloak, Sand-Bender Lady, Evil Sand Wraith, and more until Azir reached his current look. 
Azir was a benevolent leader, a kind dictator devoted to his people's well-being and prosperity. Though he got a little ahead of himself with the over-enthusiastic Ascension ritual, even that was done with good intentions, for he saw Ascension as a means to have Shurima grow and influence the entire world.
This desire was never derived from conquest, as Azir truly believes Shurima was the pinnacle of civilization and could only continue to prosper.
Azir currently wishes for the other city-states to join his empire so that they may benefit from Shurima's culture and way of life. This might prove difficult after being trapped in limbo for millennia, given the likes of Zaun are the antithesis to Shurima.
So for now Azir's motivation is to restore Shurima's glory. 
Back in the empire's heyday, Azir was popular with everyone.  This charisma might help him restore his people to greatness.
Azir's gauntlets have ribbon-like tassels to emphasize his regal status and to resemble embroidered robes which in turn represent feathers, cementing the bird-like appearance. 
When he was young Azir was taught ancient knowledge from Nasus and combat from Renekton. The Ascended brothers' teachings will prove useful for the trials ahead.
Azir himself heavily references the Dune franchise, specifically emperors Muad'Dib and his tyrant son Leto II. They are both associated with deserts and relentlessly pursue their vision of greatness for humanity, while also alluding to its inevitability.
Like The Golden Path, Azir suggests that, without himself to guide it, humanity has no future and will perish.
The scene depicted is most likely moments after his Ascension, Sivir having long departed and Azir summoning his sand army to prepare to fight Xerath, with the newly-risen Shuriman capital and the Sun Disc in the background.