lets talk about "what if" subaru return 40 years more early just to married Theresia.

lets discuss base on lore in englis languange.

To be honest, I know more or less about re zero and the book series, so I think I can theorize a little. And I only watched season 1 because I didn't have time and I hope to binge watch it this weekend. 

so some fans say, subaru pride route while he must k1ll reinhard he will use RBD just to return early and marry theresia to secure his win and when he returns in the moment fight with reinhard, the grandpa paradox work.

but there many question.

first, if the world of lugunica really have prescript and living in samsara because in the novel there literally book who fill the lugunica world story, this problem for subaru. because its mean old lagna already decide the ending and will notice the alternate.

second, i'm remmember if RBD use with Sattella agreement, so if Subaru married theresia with love, sattella will mad and set the rbd save point more short.

so in this case he must be chad and sigma for stay on his way to kill reinhard and manage to acting love theresia so she will married and make kid with him, in moment he dying.

into problem;

old lagna who "love" reinhard (joke , i know reinhard is ultimate weapon) will make the subaru plan failed by somehow after subaru die for back to moment he fight reinhard, william in past will back reclaiming theresia, take care theresia and his step son and bonding again. then from his own hips shake, reinhard parent still there and he still alive in future with new family branch of subaru son being his uncle and subaru grandson being the one who will fight against subaru himself with help of reinhard, and the bad, because this pride route, subaru grandson will try kill him to regains his family name natsuki being clear and white not bad because his grandpa idiot gameplay.

and lets say theresia is loyal and not married anyone, the moment subaru back to future, and if reinhard start die( not instant).

the old lagna somehow still have Reinhard in his database will feel the anomaly of him in the world dissapear will notice and after old lagna know subaru intervention he will some how make the reinhard fate bound into subaru and make him being subaru grandson in secure Ultimate weapon of lugunica to stay exist or decide create body for reinhard prescript then throw back bunch of DP into that body.

antoher if subaru return to future while reinhard not instant dissapear, bur reinhard memory somehow will be distract and know he as his grandpa and can't fight subaru because he is his grandpa, the moment reinhard decide to give up and die, Reinhard will being resurrected with blessing to listen and get vision from the old lagna about what subaru do.

so he will have brave and determination again to back fight subaru what if pride, because how bad he is with timeline

another but, if theresia loyal and not married also the moment subaru back there no man with reinhard face and appeareance, his name still there due to prescript and there already book with his name.

there will be person with reinhard name and story since old lagna can just force the subaru male grandson to regain astrea name and story. or even in moment subaru back his face still same because he start transform into reinhard