Lucifina/Paradox

Luka's mother is dead again by the time Paradox starts, just like in the original trilogy.

Biography
While she does not appear in part 1, we do learn some small information about her in Luka's diary. She's still Luka's mother, and she still died of an illness. Presumably. On the Ilias route, she is resurrected alongside Micaela. However, due to a lack of power, they return as Micaela-chan and Lucifina-chan. Her grave can be found at Iliasville where Luka was born. If Luka decides to help Lucifina-chan visit Snow Heaven a flashback version of her before she died will play along with a destroyed house.

Trivia

 * According to Luka's diary, she died of an illness (While this world's Ilias is still alive and she traps herself inside the Ilias Temple as Heaven was destroyed during the Great Disaster, 30 years before the events of Paradox so she couldn't be interfered with Lucifina's lifespan and natural disease as well as has no reason to do so.). Lucifina would have died after this major event if this Luka is still between the age of 15-18.
 * Lucifina didn't choose to fall in this reality. More, she was forced to due to the amount of dark energy she took in. So she didn't necessarily betray Ilias in Paradox.
 * During the pocket castle quest for teaching Rami how to fly, after Rami jumps off Mount saint Amos and fails to fly Luka tells Rami that maybe she should try jumping off from even a higher mountain and then Ilias response that even she didn't thought of that and maybe Luka has inherited cruelty from his mother Lucifina. This suggested that, at least in eyes of Ilias, Lucifina was a cruel person.