Why is Nasus so short?

Here in the new Ryze cinematic, we see a brief clip of him with Nasus against some... giant stone thing. And based on this shot Nasus seems to be... maybe slightly taller than Ryze? The perspective makes it a little difficult to tell exactly the difference, but it doesn't exactly seem to square with what we've heard of the Ascended from previous lore.

The Icathia story describes the Shuriman "God-Warriors" as they advance with their army:

"I saw nine of them, towering over the men they led. Their features and bodies were an awful blend of human and animal, and things that had never walked this world, and never should. Armored in bronze and jade, they were titans, inhuman monsters that defied belief." "Each was armed with a weapon larger than any man could lift, unstoppable and invincible. They waded through our ranks with sweeping blows that slew a dozen men with every swing."

And in Twilight of the Gods we hear about "Scores of mortal bodies tumbled into the arena, only to be crushed underfoot by the struggling god-warriors."

Doesn't exactly seem to match up with Nasus being just slightly taller than Ryze, given that Ryze isn't exactly a titan himself.

Is Nasus just really really short for an Ascended, or is this some kind of mistake in the cutscene? I'm inclined to think the latter, seeing as Nasus's own lore describes him as "a towering, jackal-headed being".