Come on lets all take it step by step.
Tae dies - prob has memories erased obviously
Karuno - chooses freedom - forgets everyone including Reika
Reika hits on karuno again and they get together as Karuno has to realise how much he likes tae again due to that situation.
That part might not be soo obvious... heres the obvious part.
Now think each line i type k see if u catch on before i say what happens
1. karuno freed - memories gone.
2. Karuno lives normal life
3. Karuno sees gantzers fighting in real life during a fight. (thats why author made them able to be seen by public now... he thought ahead)
4. reika or katou or someone else spot him and ask for help.
5. Katou becomes targetted and starts to fight.
6. Karuno losses or dies.
7. Gantzers revive him from the dead due to still being in gantz database or he gets revived after dieing by gantz.
But the writer has set it up - making people able to see gantzers ???? for what reason? Now it becomes clear. So karuno can see them during their next fight. Definatly going to be some sort of fight out in public that Karuno gets involved in... but how?
He has now forgot about Reika so what happens then??? Does that mean she has another chance to win his heart? (or does he still remember her from outside gantz... not sure)- he might even have forgotten the passed 6 months?
Only obvious part just to clear up what i was talking about is that he will see them fight.