Painting from Kamen Rider Agito explained
 

Finally a website that is kind enough to provide the information that comes from the Art Archives Icon box.
Too bad it doesn't have the information from the artist and the producer.

Quote from the website:
http://blog.livedoor.jp/sdk_photo/ar...002296275.html

Basically it says the creator Teos created the world, then created the Els and the Mal'akhs (the Unknowns or Lords).

http://livedoor.blogimg.jp/sdk_photo...d/ed5035bc.jpg

The creator then created animals based on the image of the Mal'akhs, and human with his own image. It turned the world into a paradise.

http://livedoor.blogimg.jp/sdk_photo...f/efe60d81.jpg


The humans have increased in number in time, and think they (copies of the Creator) could claim to be the master of the paradise, and will have the ability to surpass the Els and Mal'akhs.
The Mal'akhs were pi*sed, and started a 40 years long war with the humans. (200 million Mal'akhs vs 200 million humans)
Promes, one of the 7 Els, has decided to aid the humans.

http://livedoor.blogimg.jp/sdk_photo...7/07ad6186.jpg
http://livedoor.blogimg.jp/sdk_photo...d/5d1cc7dc.jpg

The crossbreed between Promes and human(s) is the Nephilim(s). (EDIT, add information from Terebi Magazine) Nephilim inherited the brutal nature of the Els, and started to feast on both animal and human. It poses as a great threat to both the Mal'akhs and human. Teos made up its mind to declare war against the defectors.
(green Nephilim = Gills)
http://livedoor.blogimg.jp/sdk_photo...4/045abc56.jpg

At the end of the Mal'akhs won the war, and Promes was killed.
The rest of the Els decided flood for 40 days, and reset the world by killing all humans, Nephilims, and animals.

http://livedoor.blogimg.jp/sdk_photo...ec0cedc4-s.jpg

Teos, had pity on the humans and animals, spared a pair of each on an arc. The Els were furious about this, and called Teos stupid.
Teos asked the Els to do another clean up next time when the world is populated again. They could then judge if the human and the Nephilims are really their enemy.

So this is the future with Agito among the people.
Agito is killing the Mal'akhs to protect the others.
http://livedoor.blogimg.jp/sdk_photo...7/f73d9eee.jpg
http://livedoor.blogimg.jp/sdk_photo...e/1e54569f.jpg
http://livedoor.blogimg.jp/sdk_photo...8/b8421fe8.jpg

Agito in red because it inherited the power from Promes (El of the flame).
The warrior in blue is G3. People who doesn't have the power of the El Lord, but are capable to fight the Mal'akhs.

http://livedoor.blogimg.jp/sdk_photo...4/947ea845.jpg

Agito, G3, and human walking on the same path, meaning the only future for human to live on is to work and co-exist with the Agitos.


EDIT:
Sorry about the broken English. It is not my first language, and I didn't have sleep for more than 3 days.

EDIT2:

So Agito was what happens when the Book of Genesis is adapted into Kamen Rider?

Uh huh...

Same thought ^ The Japanese do love their religious imagery in popular media.

The one in Decade was somewhat similiar.
Agito was missing due to the plot.

http://cdn-ak.f.st-hatena.com/images...0924201629.jpg

Eva, that is all.

Visiting the Grave of Jesus Christ in Japan

http://youtu.be/u6nEjBYqwYY

Alright, so then obvious question then: if the Els are the lords (which considering the boss lords are called Els, dead give away), are the Mal'akhs the Gurongi from Kuuga? Because I remember hearing the the lords' original task was to fight off the Gurongi for humanity's sake.

No.
According to Takatera producer's tweets both Linto and Gurongi are human worshipping the same god (a stag beetle god).
It just happened that both parties are worshipping different sides of the god.
Linto is the messenger of the god, and their warrior took the form of a stag beetle. Kuuga and Daguva's relation was a dead copy of Black and Shadowmoon.
Why is Shadowmoon white because the Great Leader in the first series had a white cape and hood outfit.
The Gurongi has nothing to do with the ELS and Lords in Agito.

Pity. Oh well, still an interesting background story.

Is Teos the Overlord of Light and Darkness then?