Inaba is Secretly Dying
- Or maybe on her period. Her strange symptoms haven't been explained yet, and trust issues don't usually constitute throwing up and fainting spells.
- No, but they do cause lack of sleep, which Inaba has admitted to.
- The most likely explanation is simply some sort of stress related illness which can very neatly be explained by trust issues plus the added stress of the whole body switching debacle.
Inaba is pregnant
- Kinda explains throwing up and fainting.
- By the Gods, it makes me feel so much better knowing that I'm not the only one thinking this. But wait, if that's the case, will that make much of a difference when she...ahem, punishes Taichi?
Number Two isn't nearly as benevolent as the first Heartseed was
- The end credits for the third arc show a child version of Taichi, and knowing how much of a troll Heartseed was, Number Two might make all five of them turn into kids at the same time. Or something.
Heartseed and Number Two are literally author avatars
- It would explain why they are trying to create conflict for no reason while at the same time not going to over the top.
Heartseed 2 is a jealous attention whore
- Heartseed was being amused by the group and even got the attention of the higher ups. Enter number 2. Heartseed 2 referred to itself with "atashi" while the original Heartseed referred to itself with "boku." This could imply that the first Heartseed was is a male and the second Heartseed is a female. Heartseed girl saw that Heartseed boy was getting attention so she wanted some action because she's just jealous. So she made her own phenomenon happen to either have fun like Heartseed boy or to get attention. Nevertheless she got the attention she may have wanted for the higher ups. Then again maybe she just doesn't like Heartseed boy and just wanted to ruin his fun.
We are the target audience of Heartseed
- Notice how we only see the lives of the kids when they have an "episode"? When they're not boring, in other words. Heartseed is there so we have a good, entertaining show to watch.
The "Heartseed entities" have a culture based around messing with the lives of humansNotice how he mentions once "They already think I'm more interesting...", but refuses to elaborate upon who "they" are. It could be that the "Heartseed entities" have a society of sorts where being "interesting" by screwing with puny humans is seen as a symbol of status, or a virtue.
There is only one Heartseed - Number Two is an emanation of itThen again, it's also possible that there is no more than one Heartseed. A rather common idea in religion and mysticism from all around the world is that transcendental beings can often "project" semi-independent emanations that part of them yet not them, in a fashion that is completely incomprehensible to human beings. It could be that Number Two is simply an aspect of Heartseed's being that decided to act in a certain fashion that the entity that is Heartseed saw fit to reintegrate it into the whole.
There is only one Heartseed - He's just trollingHeartseed is pretending that there are two to make things more interesting.