Gravion hit the sweet spot for what I was hoping to find in a mecha anime. Being a long time die-hard fan of Gundam, my expectations when it comes to mecha are always high. I have to say that Gravion definitely delivered in the entertainment department.
The story is focuses on the invasion of Earth by living robots known as Zeravire who are looking to wipe out the human race. A team of young heroes must pilot Gravion in order to save the world from this threat. One of the pilots, Eiji, is in search for his missing sister, who he finds out was a member of the organization responsible for creating Gravion. Eiji agrees to help pilot Gravion in order to find clues about his sister and hopefully have Gravion lead him to her. As the Gravion team fight the Zeravire, the motives they begin to learn the true motives for the attacks on Earth.
There were a lot of strong elements in this show that kept me wanting to watch more. I was really into the whole transforming robot deal. The concept of having individual parts make up Gravion was very reminiscent of Voltron. There were a lot of things going on in the story, way too much for 13 episodes to properly address. The whole concept of Eiji finding his sister never really ended up having closure and was left as a loose end. I did enjoy the intro theme as well as the Gravion transformation theme. The animation was also clean and nice to look at. Another positive for this show was the amount of action. Every episode had a fight scene, so there is little room for filler.
Overall, I recommend checking Gravion out. I am planning to watch the second season soon and hopefully this might provide some closure to the elements in the story that didn't get completely developed.