The secret twins

After a one night stand with Klaus Mikaelson, the 4th doppelgänger Elena Gilbert, learns she is pregnant with the original hybrid's children. But little did she know he left town due to having another one night stand with a werewolf, named Hayley Marshall.
After 8 years of keeping the twins a secret Elena and Jeremy Gilbert learn the original family is back in town looking for someone Hope Mikaelson seen in her dreams, two kids.

Season 3 of the originals.

( Hope is older than she was in the show)
(Lucien and Tristan will crush on Elena, Aurora tries to kill Elena.)
( Elena becomes a upgraded original vampire.)

( Charlotte and Grayson are slightly stronger than Hope.)