When E was lowercase, He was friend with F, R, I, N, D, and S. E reacted when F and RICK formed "frick".

Sometime before F's attack, E turned into an adult.

When he became uppercase, E got hit by F who was using D as a weapon as karma for using D to hit F. He would reside in F's cave chained up for the rest of the series until Z turned back time.
In D, F sprints at D and starts hitting him until he fainted. In E, F uses D to knock out E. They both ended being kidn