This my first fic for Drive, so I hope you guys like it.
I am a firm believer in the theory going around that Proto-Drive = Chase. My reasons are as follows:
1. Chase has already been confirmed to be using a system like Proto-Drive's and can even steal the Shift Cars and use them himself.
2. Proto-Drive and Chase's colour schemes are similar - something the design team would not do by accident or without a reason.
3. He has an aversion to harming humans, to the point that he won't fight Shinnosuke until he's in Kamen Rider form, and Kiriko seems to trigger something in him - Proto-Drive once saved her life.
4. Chase does not know who or what he is, and has been questioning this since his encounter with Kiriko.
5. Proto-Drive could not destroy the Roidmudes' cores, and Chase doesn't do that, either.
6. THEY HAVE THE SAME ACTOR! Katōno Taikō plays Chase and voices Proto-Drive in Episode 0.
EDIT 12/19/2014: 7. I just saw Episode 0, and Proto-Drive acts as straightforward and battle-focused as Chase.
This is just my theory of how this came to be. Think of how many of the classic Shōwa-era Riders got started - guy gets kidnapped by villains, who make him into a cyborg, but he's rescued before they can brainwash him. This leaves us with a guy with superpowers who retain his own willpower and has a reason to go after the bad guys, especially if they kill his rescuer.
WARNING: Descriptions of torture and gore coming up. Don't read if you get squeamish easily.
DISCLAIMER: I don't own Kamen Rider Drive or any of its characters.
WORD COUNT: 916
Pain. That was the first thing he knew when he came to. The proud bearer of the title Kamen Rider Proto-Drive (the 'Proto-' to be dropped once Krim perfected the final product) couldn't remember ever being in this much pain.
How did he get here? His last recollection was of being taken down by that powerful red Roidmude, Heart. He cursed himself for underestimating his enemy so badly.
The second and third things he noticed were two sounds. One was the sound of someone screaming in agony. The other was laughter. Sinister, seeing-you-in-pain-makes-me-happy laughter. And both were close by. He wrenched his eyes open to see a Roidmude standing over him to his right. It must have been one of the evolved ones, as there was no three-digit code to be seen on its chest. Its head was swollen, and if he wasn't mistaken, the top was designed to look like a piece of its 'skull' had been removed, revealing the 'brain' underneath. Its mouth was frozen in a cruel smile.
He couldn't find the screamer.
He barely heard the Roidmude speaking over the pain-filled cries. "The subject has awoken. Alterations to the right upper limb are complete, alterations to the left nearly so. Beginning preparations to commence the next phase of the procedure." It touched something on a tablet-like device it was holding, and the pain mounted even higher.
That was when the Kamen Rider realised that the one screaming was him. Eyes streaming, he turned his head (which took far too much effort) to see what the Roidmude had meant by 'alterations'.
Pure, unadulterated horror arose in him when he saw that he was lying spread-eagle on a metal table, stripped nude, with half a dozen robotic arms working on something silver and metal inside his left arm, which had been cut open with surgical precision all the way from his wrist to his shoulder, the skin and sinew being held apart by metal forceps. Blood pooled around the limb, but not enough to suggest that he was in danger of bleeding out. He wondered if that was such a good thing.
He turned to look back at the Roidmude, clamping down on his urge to scream further and trying to control himself in spite of the increasing agony. "What are you doing to me?!" he demanded, "What do you want?!"
The Roidmude laughed again. "You have the honour of being my first human test subject in my research on combining organic life-forms with our superior technology. I believe you understand the term 'cyborg', correct?"
He tried to struggle, but it was as if all of his muscles from the neck down had stopped working. "I'll kill you," he threatened through clenched teeth, "As soon as I get free, I'll tear you apart, down to the last cog and circuit!"
Another laugh. "Which is why I'll have to wipe your mind before letting you off this table. If the experiment succeeds, you will be a valuable soldier for us."
"If you really think I'll join you, you're- AGH!" The machine working on him did something that sent a fresh jolt of pain through his body. He looked back at his arm and saw that the skin had been moved back into place, and that the robotic devices were injecting something into various points along the limb. He watched, terrified yet fascinated, as the flesh knit itself back together. Not even a scar remained to hint at what had been done to him.
"Injection of self-repair nanites complete," the Roidmude noted, "Beginning incision of the subject's torso."
One of the mechanical arms, now sporting a wicked scalpel-like blade, moved over his chest to hover near his right collarbone. Again, he tried in vain to move away, but his body wouldn't respond. He couldn't even manage a twitch. A humming sound came from the device, the blade visibly heating up until it was white-hot.
Then the blade was brought down and pierced his skin, and all rational thought was lost as the stench of burnt flesh and a new wave of utter agony overwhelmed him.
An indeterminable amount of time later, his transformation was almost complete, only his head remaining unaltered for the moment. He'd been forced to experience metal being fused to his bones, certain organs being removed and replaced with mechanical substitutions, wires being implanted into his flesh and muscles. He'd blacked out more than once, dreaming that he was back with his friends and family, only to wake up to this nightmare all over again. His vocal chords had long since given out from screaming.
He kept hoping, wishing, praying for someone to rush in and rescue him, to pull him out of this hell. But nobody came. No one was going to save him.
Why? Why would nobody help? Had his deeds as a Kamen Rider not been worth the effort of saving him? Had Krim abandoned him? Was he not good enough to risk rescuing? How could this be happening?
He wished he'd just picked up the damn phone and called his family one last time, while he'd had a chance.
He made no noise as the white-hot scalpel sliced across his hairline, or as the whirring little circular saw separated a portion of his skull from the rest of his head.
"Commencing memory deletion and mental reprogramming," the Roidmude stated calmly.
A final tear escaped his eye as he pictured his loved ones for the last time.
THE END
So yeah, that's my theory, that he just wasn't lucky enough to get rescued. As for why Krim/Mr. Belt hasn't said anything... Well, he hasn't exactly been forthcoming with detail about the past, hasn't even told us Proto-Drive's real name yet. And it's possible that he thinks Chase is just a Roidmude using the poor 'dead' guy's face, and it's too painful for him to bring it up.