The Ender Dragon is killed by Squid's arrows. It was actually killed with the last arrow.
Stampy and Squid's Nether is composed of Blaze, Ghasts, and Magma Cubes.
Peter is Stampy's normal first dog.
Squid also records the series from his point of view.
He records the series as well.
Main Article: Quest Series
After they have defeated the Ender Dragon, Stampy and Squid had planned to continue the series. The new series was named the Quest series, replacing its older name. The current series is a sandbox series like the normal Stampy's Lovely World series, where they build things while having fun and silly.