Time Bandits

Eleven-year-old Kevin has a vivid imagination and is fascinated by history, particularly Ancient Greece; his parents ignore his activities, having become more obsessed with buying the latest household gadgets to keep up with their neighbours. One night, as Kevin is sleeping, an armoured knight on a horse bursts out of his wardrobe. Kevin is scared and hides as the knight rides off into a forest setting where once his bedroom wall was; when Kevin looks back out, the room is back to normal and he finds one of his photos on the wall similar to the forest he saw. The next night he prepares a satchel with supplies and a Polaroid camera, but is surprised when six dwarves spill out of the wardrobe. Kevin quickly learns the group has stolen a large, worn map, and are looking for an exit from Kevin's room before they are discovered. They find that Kevin's bedroom wall can be pushed, revealing a long hallway. Kevin is hesitant to join until the visage of a menacing head â the Supreme Being â appears behind them, demanding the return of the map. Kevin and the dwarves fall into an empty void at the end of the hallway.
They land in Italy during the Napoleonic Wars. As they recover, Kevin learns that Randall is the lead dwarf of the group composed of Fidgit, Strutter, Og, Wally, and Vermin. They were once employed by the Supreme Being to repair holes in the spacetime fabric, but instead realized the potential to use the map to steal riches. With the map and Kevin's help, they visit several locations in spacetime, and meet figures such as Napoleon Bonaparte and Robin Hood; Kevin uses his camera to document their visits. They are unaware, however, that their activities are being monitored by Evil, a malevolent being who is able to manipulate reality and is attempting to acquire the map himself so that he can remake the universe to his design.
Through Evil's actions, Kevin becomes separated from the group and ends up in Mycenaean Greece, meeting King Agamemnon. After Kevin inadvertently helps Agamemnon kill a minotaur, the king adopts him as his own son, something that Kevin is content with. Randall and the others soon locate Kevin and abduct him, much to his resentment, and escape through another hole, arriving on the ill-fated RMS Titanic. After it sinks, they are forced to tread water while they argue among each other. Evil manipulates the group and transports them to his realm, the Time of Legends. After surviving encounters with ogres and a great big giant, Kevin and the dwarves locate the Fortress of Ultimate Darkness, and are led to believe that "The Most Fabulous Object in the World" awaits them, luring them into Evil's trap. Evil takes the map and locks the group into a cage over an apparent bottomless pit. While looking through the Polaroids he took, Kevin finds one that includes the map, and the group realises there is a hole in the Fortress near them. They escape from the cage, steal the map again and split: Kevin must distract their pursuers while the others will go through the hole.
Evil confronts Kevin and takes the map back from him. The Dwarves return with various warriors and fighting machines taken across time, but Evil has no trouble overpowering them all. As Kevin and the dwarves cower, Evil prepares to unleash his ultimate power. Suddenly, he is turned into stone and explodes; from the smoke, a besuited middle-aged man emerges, revealed as the Supreme Being. He reveals that he allowed the dwarves to borrow his map and the whole adventure had been a test of His creation. He orders the dwarves to collect all the pieces of concentrated Evil, warning that they can be deadly if not contained, recovers the map and allows the dwarves to rejoin him in his creation duties. The Supreme Being disappears with the dwarves, leaving Kevin stranded behind as a missed piece of concentrated Evil begins to smoulder.
Kevin passes out and awakes in his bedroom to find it filled with smoke. Firefighters break down the door and rescue him as they put out a fire in his house. One of the firemen finds that his parents' new toaster oven caused the fire. As Kevin recovers, he finds one of the firemen resembles Agamemnon and discovers that he still has the photos from his adventure. Kevin's parents discover a smouldering rock in the toaster oven. Recognizing it as a piece of Evil, Kevin warns them not to touch it. Ignoring him, they touch it then explode, leaving two piles of ash. Kevin tentatively approaches the smoking ash and is seen from above as his figure grows smaller, the camera pulling back to reveal the planet and then outer space, before being rolled up in the map by the Supreme Being.

Question: Who appears behind them?
Answer: the visage of a menacing head – the Supreme Being.