I originally had no plans to add a character like that.

“when the human pilot gets in, that life is being breathed into the mech for the first time. Like, even though it's a weapon, when it moves it feels like a living creature. But when the pilot exits and it's left alone, it looks just like a jeep or tank or some regular vehicle, and once the pilot gets in and is driving it, it looks like a dinosaur.”

When Kojima reread Shibumi in 2006 as part of his research for Metal Gear Solid 4, he was startled by parallels with ideas he had already used: a combat discipline similar to CQC, the heightened threat perception he learned in scout/tracking training, and the merciful murder of a parental figure, which he related to Big Boss and The Boss. His reappraisal led him to recommend the novel to the development team.

“among the preliminary sketches I drew, one of them looked like a dinosaur, and Kojima did single that one out. "Let's go with this."”

“technical limitations of the MSX hardware made it impossible to produce a simultaneous display of the player with multiple enemies”

“I wondered if this might be the system where I could realize my original, full vision of Metal Gear… and the game that has emerged from that is Metal Gear Solid.”