This article contains spoilers
In 1998, Hideo Kojima and Konami released Metal Gear Solid, an action-adventure, stealth game that started a legacy. Though not the first title in the Metal Gear franchise, Metal Gear Solid innovated not just the action-adventure genre but video games in general, introducing fully voiced cinematic cutscenes rendered with the in-game engine. With its success with Metal Gear Solid, Konami released its sequel Metal Gear Solid 2: Sons of Liberty and prequel Metal Gear Solid 3: Snake Eater on the PlayStation 2.
In 2008 Konami launched Metal Gear Solid 4: Guns of the Patriots, taking place nine years after the events of Metal Gear Solid. MGS 4 sees the return of Solid Snake, now gray-haired and middle-aged due to his accelerated aging, on a final mission to stop Liquid Ocelot and his newly formed Outer Haven. Metal Gear Solid 4 sees the return of many fan-favorite characters, including Meryl Silverburgh and Dr. Naomi Hunter from MGS, Vamp and Raiden from MGS2, and Eva and Big Boss from MGS3. Hideo Kojima promised to wrap up Solid Snake's story along with answering many questions that were left unanswered, such as Vamp's immortality and Liquid Snake's possession of Ocelot at the end of MGS2.