|First Appearance||Issue 47 (flashback)|
Issue 48 (in person)
The being known as Zib (who prefers to call himself "the Ultimate Dib", and operates under the alias of "Zim Number 1") is an alternate universe version of Dib Membrane. In his timeline, he successfully defeated his version of Zim, but was unsatisfied and moved on to trying to wipe out all Irkens, the plan for which eventually led to him creating and ruling over the Zimvoid, disguised as Zim Number 1.
Under his alias of "Zim Number 1", Zib was first mentioned in Issue 47 by The Elder, who explained to Dib that he enslaved the Zims that were tricked by an Irken signal to fly towards Pandora's Quadrangle for an unknown reason. He created the hierarchy that put himself and his elite 100 Zims on the top, and banished everyone considered useless to the underground caves.In Issue 48, more is learned about "Number 1's" goals: he builds updated Voot Runners and weapons for the remaining Zims inside the Zimvoid and rewards them to the Zim with the highest ranking beneath himself, so they can return to their home dimension and conquer their Earth. For this to happen, the top 100 Zims are given a very strict training program that includes random combustion, as well as becoming part of the tower's security. Later, our Zim - accompanied by GIR, as well as a captive Dib, Zim 2000, and Zim 2002, with Zim Number 2 acting as guard - is called by Number 1 to be congratulated for defeating the Zim Resistance (despite the fact that it was actually the tower's guards who had done so, although they get themselves knocked out in the process) and capturing their leaders, but is soon surprised by Dib's presence. Then, to the surprise of the group, "Zim Number 1" reveals himself to be a robotic suit containing another version of Dib. This other Dib, who mockingly calls himself "the Ultimate Dib" and is dubbed "Zib" by GIR for being a merger of Zim and Dib, then explains his origins to his captives. He defeated his Zim and then the Irken Empire of his timeline, gaining great respect throughout the universe. But when he discovered the secret of Pandora's Quadrangle, he decided to use it to destroy all other Irkens - he created the signal to lure in alternate Zims, and put them through the hardships of the hierarchy so that he could enslave the strongest Zims with a "Dib virus", which can then be used to infect other Irkens and destroy them in all realities.
Dismissing our Zim as the worst Zim, Zib has the brainwashed Number 2 lock up the other Zims and GIR, before telling Dib that his universe will be the first to have its Irkens destroyed, and condescendingly assigning him to janitorial duty in the meantime (as he views Dib as being inferior for being stuck with such a dumb Zim). Dib is downtrodden at his counterpart's apparently greater success, but upon accessing his computer finds to his horror that the Zimvoid isn't another dimension, but all that's left of Zib's timeline.
As Number 2 is taking control of the Irken Armada in our Zim's universe, Dib confronts Zib, who admits that he had lied earlier - no one cared when he defeated his Zim, so he took over his Earth and used its resources to build his anti-Irken weapon, only for it to backfire and destroy his universe, creating the Quadrangle portals in the process. To Dib's horror, despite this, Zib is still determined to repeat the process on other timelines, regardless of whether they're destroyed in the process, justifying it with the fact that there are infinite timelines, so it doesn't matter if some are destroyed.Before he can continue his plan however, the Zim Resistance - whom Dib had released before confronting Zib - attack with their upgraded Voots. Zib counters with a mech designed in his image, and nearly succeeds in defeating the Resistance, before our Zim takes control of his weapon and the portals, using them to alter the timelines of the other Zims so that they're not different than him. Despite Dib pointing out that this isn't how timelines work, it succeeds in sending everyone back to their own timelines, undoing Number 2's efforts and sealing all the portals.
Zib is last seen alone in the ruins of his castle, demanding that he not be left alone.
- Zib is shown to have his PAK attached on the back of his head instead of his back. This could possibly be a nod to the episode "Ten Minutes to Doom", in which Dib gets Zim's PAK stuck on his chest.
- Despite the PAK being compatible with Irken biology, Zib was somehow able to live even after 10 minutes have passed as it was stated by Zim in "Ten Minutes to Doom" that the PAK would destroy a human body.
- Zib has two hair scythes, which seems to be a nod towards Zim's antennae. He also lacked ears and a nose and somehow had Irken teeth, furthering his transformation and making him appear less human. It's possible that wearing an Irken PAK will eventually transform a human or any other species into an Irken or alter their appearence.
- He has become extremely popular among the Invader Zim fanbase since his appearance, due to his unique origin and dark nature.
- It's unknown how Zib defeated his Zim and GIR.