Main idea: Kylo Ren was personally handed over to Snoke as a child by his parents as a bargaining chip for a peace type treaty.

Bonus- Rey comforts Kylo because she understands abandonment.
+100- Luke had no idea and throws a Skywalker tantrum/rescue mission with Rey
+1000- it was Leia's doing but Han takes the blame
+10000- Leia and Kylo confront one another and she has no remorse