So, given the whole 'I'll see you soon' bit at the end, I'd like to expect this as a weird timeline like this:
Girl is born on Earth -> Truck-sempai > Succubus > Psyche, she was in coma, now she woke up after her succubus duty is over > Guess who she finds
Elf > Sex with succubus > Die down the line > Reincarnate on Earth > Befriend Girl > "Oh noes she got truck-sempai, now I contemplate my feelings for her and realize I'm gay" > Wait until girl wakes up.
AND THEN THEY HAVE A LOT OF SEX.