I have been reading the Entity theory posed by Zeality, et al, and while I do agree it is a very plausible theory, I would like to propose another possibility that I don't feel has been adequately explored. This possibility is based off of quotes from Chrono Trigger as well as the driving force behind Chrono Cross. I am proposing that the "Entity" could be the Gurus of Life, Reason, and Time.
I came to this possibility after playing Chrono Cross and considering that the Guru of Reason planned out (most of) the events that happened in Chrono Cross. He even developed a machine which could move freely through time. As I considered this, I first thought that the Guru of Reason himself may have been the driving force behind Chrono Trigger for a few reasons:
1) He did complete the Epoch, which meant he could have used it before he decided to store it.
2) He made sealed doors which he knew would eventually be opened as given by this quote:
"To those who opened the door... I am Belthasar, the Guru of Reason. I once lived in the kingdom of Zeal."
This quote is very important because it implies that he had hoped someone would open the door and had planned accordingly. This could imply that he was expecting someone to eventually come with the ability to open the sealed door. For that to happen, they must have been able to recognize how to open the door, as we know that "dynamite won't even budge it".
From there, I considered the possibility that the Guru of Reason had planned out Chrono Trigger as well as Chrono Cross. What is interesting is the time periods the gates are placed in - 1000 A.D., the time in which the Guru of Life was sent, 600 A.D., the time period in which Magus (Janus) summons Lavos and as a consequence he and his castle disappear, 2300 A.D., the timeline in which the Guru of Reason resides, 65,000,000 B.C., when Lavos crashes onto the planet, and 12,000 B.C., where it all began for the Gurus and Janus. Each timeline represents significance to the Gurus, especially the Guru of Reason.
The more I thought about 1000 A.D., however, the more I was led to reconsider that the Guru of Reason was not the only one who could have been involved, if the Gurus were involved at all. This quote from the Guru of Life in particular led me to believe so: "Oh, my! It's...the pendant...! Er, sorry, but I can't buy that! It's...far too special! Keep it safe!" Why would he say this? One possibility, and the only conclusion I have been able to reach, is that he had some knowledge of what would eventually transpire.
The End of Time is also very interesting, as the Guru of Time resides there. Furthermore, there is the possibility that he constructed the structure of the End of Time as Crono and co. see it, since it is implied that there was physically nothing there (except the prospect of Spekkio) before he arrived. Furthermore, there is a gate in a bucket leading to the Day of Lavos there that appears to have been constructed. The question that I posed in my mind, then, was why would it not be a pillar of light like all the other gates? This gate was special in that it was not meant to be accessed immediately. Because of this, I was further led to consider the idea that the Guru of Time could have been involved in such a plan as well, especially since he serves as a guide throughout Chrono Trigger.
Since it is known that the Zeal culture was able to create and study space-time distortions, it is not unreasonable to consider the possibilty that the Gurus could have planned the formation of the gates and the guiding of the events of Crono Trigger.
Some arguments against such a theory also need to be addressed.
The first, and most compelling argument against the notion that the Gurus were involved in the planning of the events of Chrono Trigger is the gate which appears during the campfire scene. How did that gate just suddenly form?
Under this proposed theory, there is a possible answer. The pendant the Gurus made holds considerable power and demonstrated the power to make gates on two other occassions. The first occassion was the begging of the game when a portal opened when the pendant was exposed to another space-time distortion. The other time was on Death Peak when the Time Egg was used with the pendant. It must also be taken into consideration that the pendant was made of dreamstone, as was the Masamune. The Masamune did react to Frog's emotions on two occasions during Chrono Trigger, and during Chrono Cross it was full of negative emotions/energy. This gives credit to the possibility that the pendant too could react to emotion. During the campfire scene, the pendant was in the possession of the heroes, and it was also fully charged with the energy of Lavos, a being which had the power to manipulate space-time. The pendant itself could have reacted to Lucca's emotions creating a temporary gate.
Another argument is that at the end of Chrono Trigger, Lucca comments that the "Entity" is at rest. This supports the planet-entity theory better, does it not?
I hate to answer questions with questions, but this case it is necessary. How do we know that Lucca truly knew what she said was true? Also, could the Gurus not also have been relieved and at rest that their plan worked?
A third argument against this theory is that Frog's quotes from the camfire scene, " 'Tis true that mortals do relive their most profound memories before death claimeth them," and "Lavos playeth an integral role in the fortunes of this Entity..." imply that the planet is the "Entity", not the Gurus.
One possible answer is that the Gurus had no choice but to tailor the events they could plan, or even just tailor the gates to main points in the history between Lavos and the planet. After all, the whole point would be to save the planet from the destruction Lavos would bring upon it. Also, Lavos played a major role in the lives of each of the Gurus, and at least two of the three Gurus did study Lavos in detail.
I am interested in hearing feedback and other arguments, both in favor of and against this proposed theory.