|“||The last work of Guertena’s life. While the girl appears almost lifelike, naturally, she’s not based on a real person.||”|
— In-game Sketchbook's information about the "Mary" painting
Mary is a character from the game Ib. Mary holds a fake yellow rose that acts in the same way as Ib's red rose and Garry's blue rose. Mary is first seen in the fifth episode of PewDie's Ib game play and commentaries. Pewdie has said that he doesn't trust Mary, oddly enough his insticnts turn out to be correct. She can never be trusted. At first glance, her personality seems like a very childlike young girl, but in actuality, she is very dangerous & lethal. In the seventh episode of Pewdie's gameplay and commentary of Ib, it is revealed that Mary is not a real person and is a work of Guertena just like the Lady in Red, Blue, Green & the Power Rangers . As it turns out, her rose is also as artificial and fake as she is.
There are several clues in the game that Mary is not all she seems even before her true origin is revealed. Soon after she joins Garry and Ib's party, if the hallway mirror is examined again, it becomes cracked. This is probably due to the alluded idea Mary either does not have a reflection, or her reflection might've looked different from Garry or Ib's because she is not human. Also, the room Ib and Mary enter after being separated from Gary has a knife in one of the boxes. Mary asks to hold onto the knife, and then she trails off saying, "You know, just in case..."
Later Mary tried to kill Ib after being upset Garry was able to escape from the doll room she wanted to trap him in. Garry intervenes, and after a struggle, he punches Mary in the face which in turn knocks out Mary on the floor. He and Ib are forced to run so Mary can't find them. They take the only available pathway into a Sketchbook world where all the houses and scenery look like they were drawn by a 3 year old in crayon.
There are various clues to solve in the Sketchbook world to unlock keys for all the houses. In one of the houses, Garry and Ib have to hide after Mary comes in looking for them. She leaves after not finding them, but is seen wielding a weapon. Eventually, they find a house with a toybox. After peering into it, Mary appears from behind and pushes them in. Depending on the previous choices Pewds made in the game so far, the cut scene and choices to make in the toy box will differ.
Due to PewDie's carelessness and the fact that he rushed through the game, he got an ending where Mary killed Garry by plucking his own rose in a game of "Loves me, Love me not." This caused PewDie to scream on how he wants to burn Mary which oddly enough, he is able to do in another alternate ending.
In this specific ending, when Ib and Garry end up escaping the toy box after collecting Ib's rose and outrunning the evil dolls, they end up in Mary's room. She angerly confronts them about being in a place they aren't supposed to be in and if PewDie decides to run deeper into the room, there will be a painting of Mary on the wall he can choose to burn. This action alone will burn Mary into a pile of ashes like the painting did.
If Mary's items in her room are examined after her death, it is written that she wishes to leave the world she currently is in, but in order to do that, she must trap someone else in her place. Mary planned to ensnare Garry in her world so that she could leave with Ib for the real world.