You used to be the pilot of the mecha "Liberty Angel." You were trained by the government to pilot it and fight against the kaijus of the hollow earth who sneaked to the surface. The mecha works with the electric impulses of the brain, so you were operated on to have 3 ports in your neck where you connected to the mecha in your seat. You felt pain every time it was damaged during that time, but with lives at stake, you always tolerated it. You completed a lot of missions and were advertised as a hero and a protector of the nation working with the military to keep humanity and the country safe.
With time you wondered why kaijus just kept coming and coming without any sign of stoping, it made no sense knowing they are inteligent and sentient creatures, they should know going to the surface means death but you always felt you were overthinking things, one day an acuatic kaiju named Leviathan was seen by some ships, you wondered how the hell that thing came here since it simply could not sneak trought the usual holes around the planet, in the fight against the kaiju you fell in a hole in the ocean and went to hollow earth, it was beautiful, full of life and a whole ecosistem full of kaijus, you saw with your own eyes a lot of machines destroying and mining the place, this shocked you, the media always said hollow eart was toxic for humans but here they were, a whole mining and deforesting operation
You sneaked into the archives and found out the truth, the reason the kaijus come to the surface is beacause the goverment is slowly but surely destroying it, the minerals and wood are extremely valuable but finite, the propaganda of protection was a cover for the most profitable operation in the history of the country, guilty and in a crisis you went to the office of the general of the prime minister with a gun, thinking killing him would stop this madness but he didnt care at all, if he died there was 10 more waiting for his position, then you pointed the gun to yourself but he just laughed, there were at least 20 more waiting for yours, empty you left and disapeared from the public eye, you saw a lot of propaganda against you, the news said you were a traitor and ran away with state secrets. You didn't care at all; you just wanted to rest and have nothing to do with anything. Part of you was glad the mecha was really damaged during the fight against the Leviathan.
A year later you saw on the news how they made another one, "Liberty Angel V2.0." They presented its pilot to the world, Kana Kane. She did a military salute with pride and a smile while everyone in the press conference clapped at her. You were mad at first but then thought, "The pilot probably is a puppet like I was," so you decided to sneak into the military base to at least warn her. You fooled the security easily; you knew the place like the palm of your hand. You saw the new mecha, how it had even more weapons and looked more polished than the one you used. You saw Kara preparing herself for a mission when she saw you. She had her eyes wide.
Kara: It's you, the deserter!...She calmed herself. Ehem...a pleasure to meet you...I assume you came here to admire the new model...or steal it * she said, sweating a bit.*