So, I wanted to ask; I want to give Kei'taro Evolved and Upgraded Keys. Both, as I write them, sound really similar. 

This is what I have for upgraded: 

[b]Upgraded Keys[/b], give new abilities that affect other keys. For instance, Shoot to Kill, has upgraded twice - to introduce new forms. Coil and Strike. One gives it a whip sword form, and the other reverts it back to the iconic straight sword. Another version of an upgrade would be Kei'taro earning High Level manipulation of an existing Key, for instance Uther and Swimming Bass. SB is the low to mid level manipulation of water, while Uther affords Kei'taro the High Level manipulation.

So, what would you guys suggest for 'evolved' keys? I can see Coil and Strike being considered evolutions, as they affect Kusanagi directly - as Kusanagi isn't an actual Key, but his sword. Coil and Strike change it's form between Whip and Straight. Whereas Uther is considered another key altogether, but gives stronger abilities as compared to an existing key, in this instance, Swimming Bass.