That was very deep, especially for Terra. That's exactly how I think Terra's Esper side would be like : Dark, evil, cruel, nasty and with the brains.
I loved how you made the Esper side of Terra understand her well, to know how she works, thinks and acts. It was perfect, in my eyes at least.

“I’d have it no other way…it took me seventeen years to get out the first time. I can be patient…” The Esper let out another laugh, and Terra lowered her head, clenching her fist. “Don’t forget, never forget! I’ll always be right behind you, Terra.”

That part was a little amusing to me, "...it took me seventeen years to get out the first time." absolutely genius!
Well, I loved this, it was the best short fanfiction I've ever read in my life.
Thanks for the good read, pal :D

Oh, now this looks very interesting, can't wait to read more!

Gollum-Terra ftw :p