In Messiah you play Bob, a seemingly harmless Cherub armed only with wings, baby blue eyes and a little bit of an attitude and charged with the task of cleaning up earth by the Almighty Himself after it has been corrupted by someone called Father Prime. Being a Cherub isn't going to get you far in the dangerous cyberpunk inspired world of Messiah though, so Bob comes with a special trick up his sleeve - the ability to possess people. This doesn't mean Bob is involved in the human slave trade or anything like that. The way Bob goes around possessing people is actually to run up behind them and jump right inside their body to take over their soul until they die somehow at which point he makes a hasty exit and looks for another possession target. Possessing people is truly what makes Messiah unique and this inspired gameplay mechanic often lends itself to a very different style of gameplay.

Puzzles usually involve finding a particular type of person, be it a Commander, Cop, Dancer, Mechanic, Behemoth, Chot (a breed of mutated social underclass rebels) or any one of a number of different characters, and using their particular skills to get through a situation. For example a door might only be accessible by a Commander, a broken panel may need fixing by a mechanic to allow you to continue, or you may even need to possess a rat to make it through a particularly narrow air vent. Finding the right person to possess isn't always easy. While scientists treat Bob with harmless curiosity the police have been told to shoot him on site and the Chots will usually open up on you for the sake of it which can make the already interesting style of puzzles in Messiah even more so. Often a depossessed person will turn and fire on the harmless Bob, so you'll have to find entertaining ways of… disposing of them, mostly involving jumping them off a great height and leaping from their body to safety at the last moment. And then of course there are those entertaining moments when you wander into a crowded fire fight, jumping from body to body as the number of combatants slowly dwindles. There are times when you are forced to play the defenceless Bob sans possessee, and although in such times you usually have to partake in a few despised jumping puzzles, having wings to help you through makes these jumping puzzles a little less painful as Bob can glide long distances or flap these feathered appendages to gain a bit of height if need be.