(Shout-out to ADifferentSimilar is part of the theory possible...<3)

It makes sense mainly because of a lot of things. Number one, if we take a look back into the Official Trailer, Koko Ci mentions "Retak'ka is back!"

And also that dude that seriously hit that high-note-asking-pitch when he said:

This makes me think that Retak'ka could be, given the evidence and theory I formulated in the past few pages, the main reason TAPOPS was even made. (Makes sense, I theorized he was the main reason Power Spheres were abused in the first place.) Like, why would his name ring a bell to Koko Ci's mind if he wasn't 'The Legendary Retak'ka That Endangered The Most Powerful Power Sphere To Exist'?

Another proof is Kaizo and his possible significance in the plot. Perhaps Kaizo had faced Retak'ka in the past (given how he is a legendary space rebel and he has a reputation of having past conflicts with villains like Bora Ra) and failed to finish him off...

Looking at his guilty face in his 1-second appearance in the Official Trailer makes this possibility even more possible!

Adding to that, it could be that upon Retak'ka's death, the Elemental Manipulation powers have returned to Ochobot and maybe, knowing it isn't supposed to be part of the system (for an already given power to return to its respective Power Sphere upon death) Ochobot glitches and goes into dormant mode, erasing his memories in the process.

OR DID IT?!

(C'mon, people...It's obvious Ochobot was sort of surprised when he first granted BoBoiBoy his powers in the pilot episode. I mean, who wouldn't be surprised to find the most powerful ability in the hands of a 10-year-old boy if your last memory states you've previously granted it to this (↓)  smurf?)

Now that I think of it, maybe Retak'ka's memory also got erased at the moment of his 'death'! His last memory was that the Elemental Powers were his and when he got REINCARNATED (more details about that later) and woke up, his powers...were gone. And eventually, he finds it in the hands of this INNOCENT, SWEET, LITTLE, CINNAMON ROLL...

Anyway, about the reincarnation thing I'm talking about, this is where the 7 Elemental Power Spheres enter the scene. These Power Spheres may have given Retak'ka back life as an embodiment of these elements!

(Guys, I mean, really...that skin does NOT look normal!)

Besides, another proof of this entire "Element Embodiment" thing is BoBoiBoy himself! If BoBoiBoy's Elemental Powers really did originate from the 7 Elemental Power Spheres, that would explain why he turns into his Elemental Forms in the first place! BoBoiBoy Halilintar? The Thunderstorm Element's embodiment in BoBoiBoy's body...BoBoiBoy Api? The Fire Element's embodiment in BoBoiBoy's body. (Sorry if I'm being way too scientific here, but that is my point...)

Basically, this is a battle between an ancient guy that is the embodiment of all 7 Elements against one adorable little element manipulating boi...Wait, manipulating?

WELL IT LOOKS LIKE WE'RE HAVING A MINI THEORY HERE!! IS BOBOIBOY TRULY A MANIPULATOR?! FOR ALL WE KNOW, THAT COULD BE A NO!! HE COULD BE JUST RETAK'KA HIMSELF; A MUTANT PRODUCED BY THE FUSION OF INTERSTELLAR POWERS AND LIVING DNA!! IT AIN'T IMPOSSIBLE, FELLAS!!

Back to where we ended, I mentioned Retak'ka could possibly be an incarnated being out of the power of the 7 different Power Spheres. This is where we plot a brand new theory: Retak'ka's blue streak of hair...

Here are the basics to this new theory that we will later on connect with the past theories we've made. One thing we must observe are (the obvious ones) BoBoiBoy also has an oddly colored hair streak much like Retak'ka's case. Retak'ka's hair looks more of a white-grey with a shiny blue streak, whereas BoBoiBoy has either black or brown hair with a white streak.

The only evident connection we see between these two in this hair aspect could be that they both have white hair, one having more of those that the other.

But here's the catch...remember this scene?

If you look closer... Retak'ka's blue hair turns yellow.

If you don't get the picture, here me out: Retak'ka...Elemental powers...
BoBoiBoy...Elemental Powers...
Retak'ka...Odd hair streak...
BoBoiBoy...Odd hair streak...
Retak'ka...His hair changes color upon absorption of power...
BoBoiBoy...who knows...?

The main thing here is that, both have hair streaks, both have Elemental Powers...Could it actually be...a label?

Notice, it has been mentioned that BoBoiBoy didn't have the streak since birth, (I think I remember a BBB fanmail stating that, come to think of it...) and it only made its grand entrance the moment he was upgraded in the first movie. (Besides, the first BBB Api didn't seem to have a white streak in the first place unlike the modern BBB Api and Blaze. So it would be a safe conclusion that Elemental full potential given by a certain Power Sphere, which in BoBoiBoy's case is his power upgrade by Ochobot, is what triggers the so-called "The Label," which is the white streak.

So here's the main idea, why do you think Retak'ka has more white streaks than BoBoiBoy?

It could be because his power was granted by 7 different Elemental Power Spheres, therefore resulting more of that damn hair, and BoBoiBoy was only provided power by Ochobot. Basically, it's a 7 against 1 comparison.

Which holds the even bigger question: Who do you think is stronger, Retak'ka or BoBoiBoy?

DRUMROLL, PLEASE...!

There's a chance it would be BoBoiBoy...

(And, no...This isn't because of bias...)

Take a look...It's not like Retak'ka can split into three, it's not like Retak'ka can just scream, "Retak'ka Halilintar!" because first of all, that would be stupid (and creepy)...

(Like, look at Retak'ka's face...

It's like he's saying, "Wait, he can do that?!")

And given my past theories in my previous posts, it can be possible Ochobot has a separate power combined with the original 7 Elemental Powers that allows him to change form and triple-split.

In short, doesn't mean because Retak'ka has more white streaks, doesn't mean he's more powerful...It could be that BoBoiBoy's is more concentrated...

BUT, SERA, LIKE YOU MENTIONED EARLIER, RETAK'KA'S BLUE STREAK TURNED YELLOW UPON THE ABSORPTION OF SOLAR. WHY IS THAT SO?

Well, concerned reader, here comes the fun part...

Actually, the power absorption is more significant in our little theory than you think. Take note, why would Retak'ka even be interested with BoBoiBoy's powers in the first place? Let's get back to our key sentence, "BoBoiBoy is more powerful than Retak'ka." Needless to say, Retak'ka wants that power for himself.

WE THEN REACH TO OUR SECOND PART OF THE THEORY: THE ANTICIPATED PLOT...TO BE CONTINUED...