Ecco

"Oh, puddin'."

- Ecco to Jeremiah Valeska in Season 5

Ecco is a supporting antagonist in the TV series Gotham. She is Jeremiah Valeska's assistant and henchwoman and acts as a major antagonist in the second half of Season 4 and one of the secondary antagonists of Season 5.

She is portrayed by Francesca Root-Dodson.

Biography
At some point in her life, Ecco becomes the assistant to Jeremiah Valeska (who at the time went by the alias Xander Wilde) and acts as his proxy, handling his public business herself.

Jeremiah sends Ecco to capture Jerome so he can be held inside a cage. Jim Gordon and Harvey Bullock ask him to hand Jerome to the GCPD, but Jeremiah refuses. Jerome, however, sends his henchmen to hypnotize Ecco and sends her to kill Jim Gordon and Harvey and to bring Jeremiah to Jerome.

As Jerome's followers gather up after his death, a woman dressed as a Mummer in a jester costume shows up on her motorcycle at the cemetery in which they are all gathered. The leader of the troupe tells her the gathering is invitation only and tries to kill her by throwing a knife at her, only for her to block it with her wrist and blow an air horn. Gaining their attention with the noise, she holds up a voice recording to the horn, projecting a message from Jerome, giving the cult instructions to dig him up.

Jim Gordon shows up to Jeremiah's bunker and a video of Jerome begins to play on the screen. The Mummer shows up points a gun towards Jim's head and Jerome tells him not to mind her. Jim knocks the gun away and tries to fight the Mummer, but she puts up a fight back. Jerome begins being choked on the monitor. Jim gets the upper hand on the Mummer and knocks her out. He removes her mask to reveal Ecco as the Mummer, while on the screen "Jerome" is revealed to be Jeremiah with makeup. Ecco sneaks away and locks Jim inside the bunker, which explodes.

Later, Jeremiah (now with pale white skin) arrives at Wayne Enterprises. The guards ask him if he's alone and he reveals Ecco behind him, who shoots the guards. The two of them steal the keycards and use them to enter the room where all of the self-perpetuating generators that Jeremiah wants to use as bombs are stored.

After the bombs activated, destroying the bridges and plunging Gotham into No Man’s Lands, Ecco sneaks into the GCPD and glances at a map that has information about the location of all the other villains. She hears a woman radioing for Jim and hides after drawing the Cult of Jerome symbol on the map.

Personality
Ecco is extremely devoted to Jeremiah. At first, she seems calm, friendly, and professional. However, after Jeremiah becomes the Joker, she reveals a more psychotic personality, killing two guards for him and being willing to act as his accomplice in destroying Gotham. During the events of No Man’s Land, Ecco’s personality shifts to a more energetic and unhinged one. She uses roller blades, shouts angrily, and is shown snarling. She seems happy and relaxed while dancing with Jeremiah, and looks shocked when he grabs her around the throat.

Trivia

 * Ecco is based on Joker's sidekick and girlfriend Harley Quinn from the DC comics and other media, although it is unclear if Ecco is indeed Harley Quinn or a predecessor to the character. In the Season 5 trailer, Ecco can be heard saying “Yohoo Puddin’”, which is what Harley famously calls the Joker.
 * Ecco will return in Season 5 and will gain a new costume and an appearance that is closer to Jeremiah's. Her outfit bares a slight resemblance to Harley Quinn’s outfit in Arkham City.
 * In the Season 5 premier, Ecco looks like she did at the end of Season 4 and still has her stoic personality, implying something will happen to her that will make her become more unhinged as the season progresses.