Fans have been trying to guess the identity of Felicity Smoak's father since season 2 of The CW's superhero drama. Given her intelligence and tech background, fans have theorized that Smoak was the daughter of such DC Comics characters like Lex Luthor, Mad Hatter and even the likes of Dr. Niles Cauldervor or Will Magnus. Then, when Arrow showrunners confirmed that Felicity's father would turn up in season 4 of Arrow, many fans theorized that her father was Damien Darhk. However, this theory was quickly refuted and Darhk's recent actions would certainly indicate that Felicity is not his daughter. Then, new broke that Tom Amandes would be turning up on Arrow to play The Calculator and all signs pointed to him as Felicity's father. But whey does Noah Kuttler turn up in Star City now, of all times? Many fans believe that the character in the grave is actually Felicity's mom and that The Calculator shows up in Star City to get his revenge against Darhk.
Recently, Arrow executive producer Wendy Mericle did confirm that The Caluclator does have ties to Felicity. "We are very excited about this character. He does have a connection to Felicity. We're just really thrilled. Tom Amandes has been amazing in the role and is bringing a lot of kindness and a lot of malice to this character."
Amandes is confirmed to appear in two episodes this season, beginning with s04e12, "Unchained" which airs in two weeks.