Under the Umbrella

We know that the symbols were made by Artakha at the same time as the transformation of the Mata into the Nuva, with the symbols becoming tied to their elemental powers and actually containing that power. We also know that for some reason, if the symbols are possessed by enemies of the Nuva, their link to the power within the symbols is severed and they lose the ability to use their elemental powers.

I’ve talked about this before in my Marendar based fanfic “salvation”, but it always seemed odd that the Nuva needed their powers to be held somewhere other than their bodies - we have examples like the Makuta and the Elemental Lords where they had elemental powers stronger than the Nuva without needing an outside receptacle for them, so its unlikely that the symbols were needed because their powers were too much for their bodies to handle. In the fanfic, the solution I came up with was that while their powers were not too much for their bodies to handle NOW, they would become so in the future, using the evidence of the later revealed Nuva ability to set up a delay on their powers as proof of their powers growing over time. So Artakha made the symbols and tied the Nuva powers to them to protect the Toa Nuva from their own powers in the long run. While I didn’t write this part up in the fic itself, I also had a headcanon that in this scenario, the powers would one day grow so large that even the symbols couldn’t contain them, so they needed to be combined together with the cube to expand the storage space so to speak.

However, one other intriguing possibility is that the symbols were a failsafe in case the Nuva ever went rogue.

There are plenty of intstances in the history of the Matoran Universe of the corrupting influence of power, and Toa have proven to be as susceptible to this as anyone else - just look at what happened to Tuyet with the Nui Stone. Maybe thats why their power was held in the symbols, and why Artakha added in the limitation that their connection to those powers would only be in effect if the symbols were in the possession of allies. As long as the symbols were in the possession of the Matoran, the Nuva would lose their powers if they ever turned against those they were sworn to protect. The instant the Matoran were no longer considered allies of the Nuva, the Nuva would lose their powers and their ability to harm the Matoran with them. That’s why the symbols were teleported to the villages upon their activation and not directly to the Toa, it was always the Matoran who were intended to be in possession of them. The fact that enemies could steal the symbols and also rob the Nuva of their powers would just be an unintended side effect in this scenario, one that the Bohrok-Kal took advantage of.

So what about the Nuva Cube? Well, Greg has said a few time that this was made as a failsafe by Artakha, but has always failed to elaborate on WHAT it was a failsafe against. I think we can extrapolate from both canon and the Symbols theory above to answer this.

We know that a protodermis cage made by a group of Toa can only be unlocked by the same elemental powers that created it. Just before their transformation into the Toa Nuva, the Toa Mata had created such a cage to trap the Bahrag and stop the rampage of the Bohrok Swarms. Artakha knew that while the Bohrok were released early and therefore needed to be stopped in this instance, it was critical that they be allowed to do their jobs again when the time was right. That meant that at some point, the Nuva would need to recombine their powers and release the Bahrag from their prison.

Teridax also loves to speak at length (or at least hear his own voice).

Son of Makuta - Accuracy

"Can pin a fly to a tree from a hundred yards away without killing it.”

Source

He wants the Vahi for unknown reasons, and is always seeking it. But he doesn't want to use it. He's apparently just content to sit there and hold it. He has zero ambitions outside of having the Mask of Time and will just sit there and watch it while other people try to get it. But also nobody can take it off of him because his time distortion field, so it's very difficult to get it away from him. The combined result of this is that he literally doesn't notice when people attack him, because he never gets hit.

Time Trap is structured around him, because he serves the purpose of forcing the teamup between Vakama and Teridax, which is basically the entire point of the book- Letting Greg write a bunch of Teridax scenes to establish his version of the character and repair his rep after three years of him being a fairly non-threatening Disney Villain.

The most there is to say about Voporak's contributions besides "Hold the Vahi so the plot can happen" is the things that are done to him, like Teridax throwing a legion of Rahkshi at him, or Teridax power-bombing TSO into him.