In the beginning, when Lucius was little, his father lucifer wanted him to bring chaos to the starling city.
The first time lucifer was angry, he sent the war. Now he is more angry, he sent his son lucius to to his dirty work. Lucius was still young, still a baby so he had been taken care of until he was ready.
Lucifer sent Lucius along with an army and four horsemen to help him do his work.
Along with four very angry horsemen that are powerful than any other human or alien combined.
He angry and looking for vengeance. He will give what the world has given to him, Desperation.
The Justice Team which includes green arrow, the flash, supergirl, firestorm, and the atom are trying to stop him and his army but now is failing.
In the end:
green arrow, the flash, supergirl, firestorm and the atom all die and lucius, the four horsemen and his army invade and take over starling city just like Bane did in gotham city.
The End. Not a good enough ending as you thought aye??? Deal with it.