[@Shoryu]

Hey Shoryu! So, as for your characters, I was going to wait until we got the history to add my input but I'm not sure when that'll come in so I'll just tell you what I'm seeing now.

As far as Grinder goes, I really like the concept but there a just a few issues. 
[list][*]He's very large, 140 meters when not hunched over is a bit much. 100 meters when standing straight would be more appropriate. 
[*]Mineral Shaping is fine as far as when the crystals are on his body, however flinging them through the air and shaping them seems pretty unrealistic. If he could just shape them on his body to become sharp armor that may make more sense. 
[*]If you're still looking for a long range attack, you could extend the range of the beam he has. Also, an explanation on how he varies the beam's power could be a great addition.[/list]

Other than those qualms, Grinder seems fine by me! 

As far as Gaia is concerned, I only have one small issue: 
[list][*]So, for the shaping of its body, making a shield or blade out of the metal coating doesn't make as much sense as the other attributes you included for the shaping. Making spikes form all over its frame, or upping the durability of the parts it uses to stomp/beat the other kaijus could be a good alternative.[/list]

That's all I've got to add!