Timeline

nothing much yet but basically in some near future, a 'gate' or rift in the sky opened and creatures who initiated the looks of actual angels went out, wrecked havoc til humanity fell apart. After some time a real archangel miraculously apparently appeared, killing a lot of those creatures but died so due to exhaustion. The remaining humans were able to track where the dead archangel's body fell and they obtained its genes which they used to create Espers who can fight against them evil creatures, Eve/Michael (blonde w purple eyes) being the very first one.

He was a failure cuz he's so unstable, but they still kept him alive even after they made more generations of espers cuz they needed his genes for it. Adam served in the military(? and they were tasked to escort Espers to the gates to fight.

Present day — the espers program was a success (there's barely any sightings of the evil creatures) and now there's a debate on what to do with the espers, cuz technically their job is done and they're too powerful to keep alive (morality at play). Rian tells a now retired Adam that the gov(? will now hire Guides for the Espers so they can blend in w society easier. Kayla the other Esper Adam met at the cafe with his friend told them that Eve will be disposed of as it was meant to be in the first place. Adam rushed out and called Rian, requesting a contract be made cuz he will be Eve's guide.

imitated** but well ¯_(ツ)_/¯