I wrote this a while ago, figured I may as well post it here. it's based on the Epic of Gilgamesh, in fact some sections its pretty much find/replace Gilgamesh with Emperor. Comments/criticisms welcome

He who knew the Past, Mankind’s foundation,
[who] knew…,was wise in all matters!
[The Emperor, who] saw the Past, Mankind’s foundation,
[who] knew…,was wise in all matters!

He who knew the Future, Mankind’s destiny,
[who] knew…,was wise in all matters!
[The Emperor, who] saw the Future, Mankind’s destiny,
who knew…,was wise in all matters!

[He]…everywhere…
and [learnt] of everything the sum of wisdom.
He saw what was secret, discovered what was hidden,
He who lived before the Strife.

He [rebuilt] Terra after it fell.
His armies were many, their weapons were strong,
All bent their knee to his rule,
None could deny the Lord of Mankind.

Surpassing all other kings, heroic in stature,
Mighty lord of Terra, wild bull on the rampage!
Going at the fore he was the vanguard,
Going at the rear, one his comrades could trust!

[The Emperor is] tall, magnificent and terrible,
who opens passes in the mountains,
who rebuilt the factory and the fortress,
who crosses the void, and made peace with Mars.

Mighty Lord of the machine, all artifacts are known to you!
[who] knew…,was wise in [all matters!]
All machines bow before you,
your wisdom makes you their lord.

The Adepts of Mars heeded His wisdom,
they built great devices in His name.
Great ships and weapons are His to command,
The armies of mankind are restored to glory!

See the mighty armies of Mankind!
More warriors than can be seen,
strong of arm and brave of heart!
Were their weapons not the finest?

See the war-fleets of Mankind!
Have they not the thickest hide?
With macro-cannon and plasma driver,
His enemies are smashed to atoms!

Titans of Mars, mighty gods of war
Stride across the field, shields raised high!
No weapon can harm you,
Your every foe is vanquished!

[…]

The Emperor awoke from dream, but was not startled.
His Will is the bastion of mankind
He consulted his sages, who opened their mouths to speak;
“Mightly lord, your vision is an omen”

“Many enemies does mankind already have,
[Daemons plot] out [our] doom, his ghosts and daemons
are lothsome … We should train more men,
and build more titans until no more can be built”

The Emperor opened his mouth to speak
“we need not men nor Titans, but [gods of our] own!
I will forge with my wisdom and power a score of
[men like] gods to lead the host of mankind”

[…]

The Emperor gathered up his finest seers and tech-wizards
And traveled deep into the Imperial palace.
In the bottom-most dungeon was His reculsium.
He closed the door and did not return for 7 years.

At the end of the first year, his followers grew worried,
They sent a great warrior to the bottom most dungeon.
At the great obsidian door, gateway to the geno-labs,
He called out “Noble Emperor, lead our armies once more!”

The warrior waited at the obsidian door,
On the third day the emperor spoke into his mind.
“Great warrior”, said the Emperor, “I am not yet done,
in six more years you may return.

At the end of the second year, his followers grew worried,
They sent a great scholar to the bottom most dungeon.
At the great obsidian door, gateway to the geno-labs,
He called out “Noble Emperor, teach your wisdom once more!”
The scholar waited at the obsidian door,
On the third day the emperor spoke into his mind.
“Great scholar”, said the Emperor, “I am not yet done,
in five more years you may return.

At the end of the third year, his followers grew worried,
They sent a great seer to the bottom most dungeon.
At the great obsidian door, gateway to the geno-labs,
He called out “Noble Emperor, guide your people once more!”

The seer waited at the obsidian door,
On the third day the emperor spoke into his mind.
“Great seer”, said the Emperor, “I am not yet done,
in four more years you may return.

At the end of the fourth year, his followers grew worried,
They sent a great navigator to the bottom most dungeon.
At the great obsidian door, gateway to the geno-labs,
He called out “Noble Emperor, guide our ships once more!”

The Navigator waited at the obsidian door,
On the third day the emperor spoke into his mind.
“Great Navigator”, said the Emperor, “I am not yet done,
in three more years you may return.

At the end of the fifth year, his followers grew worried,
They sent an Adept of Mars to the bottom most dungeon.
At the great obsidian door, gateway to the geno-labs,
He called out “Noble Emperor, command our machines once more!”

The Adept waited at the obsidian door,
On the third day the emperor spoke into his mind.
“Great Adept”, said the Emperor, “I am not yet done,
in two more years you may return.

At the end of the sixth year, his followers grew worried,
They sent Malcador the Sigilite to the bottom most dungeon.
At the great obsidian door, gateway to the geno-labs,
He called out “Noble Emperor, rule Mankind once more!”

Malcador waited at the obsidian door,
On the third day the emperor spoke into his mind.
“Loyal Malcador”, said the Emperor, “I am not yet done,
in one more year you may return.

At the end of the seventh year, his followers grew curious,
They sent Constantine of the Custodes to the bottom most dungeon.
At the great obsidian door, gateway to the geno-labs,
He called out “Noble Emperor, what have you created!”

The obsidian door opened, the guardians stood aside,
Noble Constantine beheld mankind’s past. There
in the bottom-most dungeon were His Geno-labs,
Built before the fall, the Emperor’s reclusium.

Constantine stood before his master, Lord of mankind,
At His side, a score of babes, perfect and terrible.
“Noble Constantine”, said the Emperor, “behold,
for they are what you were to be”

And Constantine of the Custodes beheld the Primarchs,
fathers to the Legions, Gods among men.