Terra e... (TV), No.6 Recommendations
The beginning of the story is the same and Sion resembles to Jomy Marcus Shin.
Sci-fi's where a boy lives in an advanced and tightly controlled society, but then gets in trouble with them, and must flee. Even though his life is at risk, he wishes to return. Shion and Jomy are both very impulsive (though Jomy is probably a little more intelligent). The boy has a mentor figure who introduces him to his new life in the outside world (Nezumi is like a cross between Blue and Keith). There's a little flavor of 'bromance' too.
Both are set in a futuristic setting in which the government wants to have full control over it's residents. They also share the same type of protagonist, a young boy suddenly ripped out of his surroundings and now has to learn the truth behind his ideal world. You also can see some similarities in other characters like Nezumi is pretty much like Keith.
both narratives are structured similarly - they begin in almost the same way and tell a long story of struggle against the oppressive future dystopian system. There is also similar dynamics between pairs of certain characters, which connects with the fact that both series have shounen ai undertones (although in No. 6 vastly more apparent).