Jack and Tip/Ozma
Theories:1. Jack will become The Tin man after he gets injured by Eammonn/Cowardly Lion in a fight when he and Tip/Ozma tried to leave the city of ev and Lady Ev turns him into a 'cyborg' and gives/sells Tip to West.
2. As Tip will go through what the tin man's girlfriend went through in the original stories from the books.
They get sepearated and have to find each together before this series ends.