I'd like to identify this anime TV show or movie.  I saw it about 6 years ago, late night, on Cartoon Network/Adult Swim/Toonami/Boomerang, in English language.  At the beginning of the show there was these monsters that were attacking a village or a town and then this girl gave him a gem that was on her forehead. The gem bonded to him and then he fled away from the destruction. There was about 5 to 8 people that had these "gems" and they were teaching him how to use and how to transform into these bio monsters.   There were different elements: one guy had the water element. But the kid had a special type of "gem" that nobody knew what his powers or limit was. The crystal or gem was blue.
Typical Japanese style anime art, it was a series.   It has been around for more than 6 years. I think it mixed fantasy and sci-fi. It was certainly not Isekai and it has no magic, it feels more like revered science. A boy gets a gem embedded into his arm after a terrorist attack and transforms into a white and orange humanoid being. There are more people able to transform into these beings. There is also a red flying ship with a dark yellow underbelly that throws boxes with parachutes. There is also this top-secret laboratory where the scientists study how to battle against the beings. There are some other flying ships of varying colors. If I remember correctly, the protagonist gets amnesia near the end of the plot.
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