The Warden is described as someone young, inexperienced and in way over his (or her) head.
With my project being based around a dinosaur zoo/them park/science experiment gone wrong, I altered the Warden idea to a head scientist (or even vet) of the park. Brilliant in his field, and a young genius, he gets hired. He soon discovers the genetic mutations that are taking place and is forced to work against his will, despite his objections. He's young and scared and easily manipulated. He hides and has survived the events of the last year on the island.
I wanted the Warden to be one of the earlier characters Chloe (the player) meets in the game. He'd be the guy with the 'plan', helps out with information, tells the player what to do, how to attack and avoid the varying species of dinosaurs etc etc. So, to stop him from wondering around with the player during the game (survival in numbers and all that)...I broke his leg during a recent dinosaur attack, immobilizing him. That'll slow him down.
I also named him Warden Gorman after the wonderfully inexperienced and in over his head Lt. Gorman from Aliens :)
Here's some of the early design work, leading up to the final piece:
