Nandato?!
Brain children would be born every time Levi kicked Eren to protect him. Creating a brain child doesn't require being smart. Please, young bocchan, don't forget that this is real life, a simulated harem. YOU are the protagonist. Do you need to be smart? Handsome? Talented? Able to do anything? Of course not!
It doesn't matter how unattractive you are, you will have females fawning all over your generic face!
Eren screams and every scream creates a new child. Every look of constipation on Levi's face births another. Each and every one of those children are born with innate fujishi or fudanshi-ism. Each one multiplies, they perform mitosis. The number of yaoi-loving children will grow exponentially!
Just imagine this future. You are in your room; there is nothing there because the torrents of fujoshis/fudanshis took it all. But you can rest in peace knowing that EreRi IS canon.
In your honor I would even, personally, make your tombstone. Don't worry, you won't turn into a zombie or anything. This isn't Sunday Without God for kamisama's sake. You would be laid to rest beside other famous people who truly changed the world for the better. People like Albus Dumbledore (#Harry Potter) and Sasuke Uchiha (#Naruto).
In conclusion, we still need to play Hearthstone.