Personality Analysis
First and foremost, Data Sora’s Heartless is actually quite intelligent. He is one of two Heartless in the series able to speak, and he also formulates a plan to escape the journal into the real world. This is something unique to him, and the only other Heartless that shows any form of intelligence beyond mindless consumption is Xehanort’s Heartless. Of course, that’s not to say he isn’t driven by hunger, but so is any Heartless. (“Ones born of the heart and darkness, hunger for every heart until the dark door opens.” and “RAGE… HATRED… GLITCHES TO FEED MY DARKNESS. AND SOON, HEARTS TO SATE MY HUNGER.”)
Adding to this, he figured out a way to become stronger-something no other Heartless in the journal tries to do. He proved to be resourceful, using the glitches and even the minds of the Heartless to feed his strength. (“Your Heartless has been gathering up, then devouring the dark intentions of the fallen Heartless. That’s where it gets its power: dark data!” and “Defeating Heartless here in the datascape, though--that wouldn't have set any real hearts free. Instead, you've releases the Heartless's minds.”) His speech patterns also demonstrate an intelligence that even Sora doesn’t seem to have, and he uses words much more similar in pattern to Ansem then Sora. (“LONG HAVE THE FALLEN WANDERED. NOW THEY SHALL SERVE THE WILL OF DARKNESS.”)
He also shows and extreme amount of patience. He quietly waits while Data Sora and Data Riku speak and figure things out. He also had the patience required to remain hidden while he devoured said glitches and minds, and Riku-the very avatar for the journal-had no idea he was even doing this. (“Wait...that's it! You're not the only one who evolved within the datascape!” combined with “I know where the bugs came from. All of them! It's your shadow--your Heartless!”)
It is later revealed, though, that while he is not the source of the bugs, he makes them worse. The source is Naminé (“Memories used to fill Jiminy's Journal, but when they were pulled apart and then stitched back together... bugs appeared.”), and Sora’s Heartless simply takes advantage of the bugs-again, demonstrating both intelligence and resourcefulness that only Xehanort’s Heartless shows. (“I know where the bugs came from. All of them!”)
It is suggested through his own words that he experiences at least some degree of emotion. His word choice carries a tone of smugness, and he even comes across as taunting. (“LONG HAVE THE FALLEN WANDERED. NOW THEY SHALL SERVE THE WILL OF DARKNESS.” and “RAGE... HATRED… AND NOW, GLITCHES TO FEED MY DARKNESS.”) At the very least, he is extremely confident of himself, both suggested by his own words and by how he allows Sora and Riku to converse when he could have simply initiated a battle right off. (“RAGE… HATRED… GLITCHES TO FEED MY DARKNESS. AND SOON, HEARTS TO SATE MY HUNGER!”)
He’s also very, very determined to achieve his goal of escaping the journal. This is evidenced by how he does not accept defeat, instead drawing on his data and evolving once more to a human shape. (“Why is it looking at me like that?” and “When is this gonna end!?”) In fact, he perseveres to the point that Sora is weakened and unable to defeat him alone and Mickey himself has to intervene to keep the Heartless within the journal.
He is also extremely, extremely devious. Starting just after the Coliseum level, there are screens talking about recovering and assembling data, starting at 10%. This number steadily climbs higher and higher until, at 100%, this message is shown:
DATA RECOVERY... 100%
DATA ASSEMLY COMPLETE
GLITCH FOUND IN DARKNESS
AWAKENING DARK GLITCH
DELETE DATASCAPE YES/NO?
Y E S
Riku then goes on to say that whatever is trying to delete the datascape is the one who was controlling the bugs. When this is investigated, it is revealed to b none other than Sora's Heartless. He had, this entire time, used all of Sora's efforts to clean to Journal to his advantage and built himself up so that no one could stop him, proving himself to be quite the clever little thing.
Adding to this, he figured out a way to become stronger-something no other Heartless in the journal tries to do. He proved to be resourceful, using the glitches and even the minds of the Heartless to feed his strength. (“Your Heartless has been gathering up, then devouring the dark intentions of the fallen Heartless. That’s where it gets its power: dark data!” and “Defeating Heartless here in the datascape, though--that wouldn't have set any real hearts free. Instead, you've releases the Heartless's minds.”) His speech patterns also demonstrate an intelligence that even Sora doesn’t seem to have, and he uses words much more similar in pattern to Ansem then Sora. (“LONG HAVE THE FALLEN WANDERED. NOW THEY SHALL SERVE THE WILL OF DARKNESS.”)
He also shows and extreme amount of patience. He quietly waits while Data Sora and Data Riku speak and figure things out. He also had the patience required to remain hidden while he devoured said glitches and minds, and Riku-the very avatar for the journal-had no idea he was even doing this. (“Wait...that's it! You're not the only one who evolved within the datascape!” combined with “I know where the bugs came from. All of them! It's your shadow--your Heartless!”)
It is later revealed, though, that while he is not the source of the bugs, he makes them worse. The source is Naminé (“Memories used to fill Jiminy's Journal, but when they were pulled apart and then stitched back together... bugs appeared.”), and Sora’s Heartless simply takes advantage of the bugs-again, demonstrating both intelligence and resourcefulness that only Xehanort’s Heartless shows. (“I know where the bugs came from. All of them!”)
It is suggested through his own words that he experiences at least some degree of emotion. His word choice carries a tone of smugness, and he even comes across as taunting. (“LONG HAVE THE FALLEN WANDERED. NOW THEY SHALL SERVE THE WILL OF DARKNESS.” and “RAGE... HATRED… AND NOW, GLITCHES TO FEED MY DARKNESS.”) At the very least, he is extremely confident of himself, both suggested by his own words and by how he allows Sora and Riku to converse when he could have simply initiated a battle right off. (“RAGE… HATRED… GLITCHES TO FEED MY DARKNESS. AND SOON, HEARTS TO SATE MY HUNGER!”)
He’s also very, very determined to achieve his goal of escaping the journal. This is evidenced by how he does not accept defeat, instead drawing on his data and evolving once more to a human shape. (“Why is it looking at me like that?” and “When is this gonna end!?”) In fact, he perseveres to the point that Sora is weakened and unable to defeat him alone and Mickey himself has to intervene to keep the Heartless within the journal.
He is also extremely, extremely devious. Starting just after the Coliseum level, there are screens talking about recovering and assembling data, starting at 10%. This number steadily climbs higher and higher until, at 100%, this message is shown:
DATA RECOVERY... 100%
DATA ASSEMLY COMPLETE
GLITCH FOUND IN DARKNESS
AWAKENING DARK GLITCH
DELETE DATASCAPE YES/NO?
Y E S
Riku then goes on to say that whatever is trying to delete the datascape is the one who was controlling the bugs. When this is investigated, it is revealed to b none other than Sora's Heartless. He had, this entire time, used all of Sora's efforts to clean to Journal to his advantage and built himself up so that no one could stop him, proving himself to be quite the clever little thing.