Before Operation Impending Doom, Zim accidentally killed the previous two Tallests, Miyuki and Spork. ... The Tallest often underestimate Zim; even though he is lightyears away from Operation Impending Doom II, he still manages to mess things up for his people.

What happened to the tallest in Enter the Florpus?

Jhonen Vasquez has confirmed that both Red and Purple are deceased, having died in the Florpus Hole in the dimension of fire, and presumably met their end shortly after Zim's transmission with them disconnected.

Do Zim and Dib become friends?

In the end, as their ships sink, they're last seen laughing together. In issue 50, when the new student Chammy Wamboo sees how Dib and Zim constantly fight and are against each other, she has a strong urge to help them become friends, managing to make both of their robots become friends as well in the process.