<p>For those questions, here are a few theories:
</p><p>He/she was probably sealed inside Hajime by J.J. since Katse was too dangerous to let loose on the world and others. For Katse this was worse than death since he hates everything other than misfortune while Hajime stays positive in everything.
</p><p>I can't really say much about the plot plan but this was aimed at a modern audience to reintroduce a popular yet decade's old series while using elements from modern pop culture like social media. If you ask me this was more about promoting Gatchaman rather than reintroducing it, which can cause fans of the show to get an interest and look back on its source of material. Especially since the live-action Gatchaman film opened a month after the show premiered.
</p><p>But again, these are just theories.
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