I got this idea cause my niece was watching the animated astro boy film and the only part of the movie i remembered is the star core stuff. So im gonna use that.
So A star fragment is hurtling through space, burning a bright purple when it happens to soar towards earth.
When it breaches the atmosphere it is torn apart, one fragment blue and the other red.
Of course people come and collect the fragments, and they take note of the properties of the fragments.
The blue seems more stable then the red, the blue is calm, while the red seems wild.
The fragments seems to become more unstable the closer they are to each other so they are separated, with the assumption bad things will happen when they are brought together.
Two androids are developed to test the fragments, L4NC3 for the blue core and K13T5 for the red core.
The android were to never meet and kept in separate facilities for monitoring.
The androids tho, unbeknownst by the scientists, held the fragments conscienceness'.
The fragments wanted to be together, the more stable of the fragments knew this very well, that it was incomplete.
The unstable red fragment tho, was forgetful, it did not know what it had lost or what it was missing, it just knew that it was missing something.
While the L4NC3 begged, the K13T5 lashed out.
Allura and shiro were the scientists in charge of K13T5.
Hunk and Pidge were the scientists in charge of L4NC3.
Endgame is them both breaking out of their facilities and finding each other, both desperate to be whole again.
When they finally come together (much chaos and panic from the scientists expecting mass distruction) It is less destructive and more just a pretty light show.
K13T5 and L4NC3 go back to being together and its all happy and gay (and i probably cried).