Why did de Jaardan create the Angara?

As far as I can tell there was no explanation in the game. The whole "who are the Jardaan, where are they now and what the heck were they thinking"- storyline was left open, I hope to be continued in another game/DLC and not as eternal mystery.

There have already been some speculations about the purpose of the Angara scattered over several threads, just a summary what I remember:

• the Jardaan are an AI and      
  
  • built them to be their slaves
    
  • intended to/already did download their consciousness into organic bodies
    (the Angaran genetic memory thing, though what you would want with a
    decaying organic body when you are technically immortal is beyond me)
  • killed their creators in some sort of morning war, regretted it at some
    point and "rebuilt" them, along with whole ecosystems they probably
    destroyed during that conflict as well (hence the vaults and terraforming)
• as some sort of experiment for a research project
  
• because they could. Duh.

The thing that worries me is Jaal's reaction to the revelation his people were engineered. When you talk to him back on the Tempest he isn't upset or shocked (not much, anyway). He is excited about the whole thing and eager to find out what their purpose is and how to fulfill this purpose as best they can. His reaction could be part of their "programming", Jall himself said something to that effect.
If the Jardaan ever return I bet we will have lots of fun with our Angaran "allies".

Perhaps it was the Leviathans. They were able to travel dark space. They needed the races in Milky Way to be their hands to build things, controlling people with the artifacts. If some of the Leviathans escaped the Reapers through Dark Space then they would need to have sentient slaves to control and those slaves would need habitable worlds.

They wanted sex slaves obviously.

Not sure that's true.  You can mix the chemicals up in a lab to create life.  I mean, that's essentially what happened in real life and it evolved into what we are today.  I see no reason why the Jardaan couldn't do the same.

No, I'm not suggesting "creating" raw materials.  I'm talking abiogenesis, taking non-life and turning it into life.  To me, that's creating life.  So we've got this mix of chemicals (amino acids on Earth), mix in some other chemicals (early days of Earth the atmosphere was toxic) and then add electricity.  Get that going, make it all metabolize and it might just evolve into something.  In this case, that something is the angara.  Just because we can't yet do it on Earth in no way means that it's impossible to create life.  I suspect it's going to happen.

It's just as possible the angara are a product of genetic engineering (altering what already exists) but I wouldn't call that "creation". 

Chart below suggests how life could be created in a lab.  Spoilers for size reasons.

Funny I was going to reference Prometheus since I just saw it...for the first time.

Anyways I think it was clear they were guardians, keepers, caretakers, maintainers of the vaults and all the tech. Just think about sentient Keepers I guess.

I'd suggest you stop reading 'creation science' websites. They're all bogus, filled with lies and gross misrepresentation of data and facts.

I have a feeling the Jardaan's motives are going to have a big reveal in the third Andromeda game, much like...