Dr. Stein

Dr. Stein is the main antagonist of the event game Hallow's Eve 2017: A Tale of Lost Souls, and is a supporting villain in Egg Hunt 2018: The Great Yolktales.
Bio

Dr. Stein may seem nice at the start, but it turns out that he is evil and he used the player to free the souls of the trapped others, only to use the souls to bring his creation to life.

Hallow's Eve 2017: A Tale of Lost Souls
In the beginning of the game when the player enters the house, he/she is greeted with Dr. Stein, who thinks he woke the player up from a nap. He tells the player that he needs help freeing the souls he accidentally trapped. he tells the player to reach the portals and go to different worlds and he'll let the player leave.

In the fourth portal, Dr. Stein's nephew Billy appears as a ghost in present time. Billy's uncle Dr. Stein sent him out to see if he can get some candy for his creation called Frankie, but zombies are ruining everything. Billy gives the player a Nerf Zombie Strike Dreadbolt gun, which afterwards becomes the prize that the player earns, and tells the player to help defend Frankie's candy.

After the candy is defended, Dr. Stein tells the player to come to his lab and meet Frankie, only to reveal that Dr. Stein is evil and wanted to use the souls and the candy to bring Frankie to life. After Frankie comes to life, Dr. Stein is thrown across the room, knocked out in the process. It is revealed by the narrator that Dr. Stein escaped and is planning revenge.

Egg Hunt 2018: The Great YolkTales - Stein's Basement
Dr Stein returns for revenge. He created a new monster he calls Frankenrat. The player has to lure Frankenrat underneath three cage traps, so that he can get an egg for a prize. as the Frankenrat is trapped underneath the third cage trap, Dr. Stein says that he'll come back.

It's presumed that he'll return for another event.

Trivia
His name "Stein" comes from in Frankenstein.