|1st appearance:||Hostile Makeover|
|Voice Artist:||Cristin Milioti|
Sirena Ong is the daughter of super-villain Wide Wale. She lives with her father in the New York penthouse of Tophet Tower.
Sirena first appears in Hostile Makeover, where she is seen by Hank (using Brock's binoculars) jumping into a pool but looks as if she was unresponsive which causes Hank to steal Brock's grappling gun to make it to her building where he discovers that she possesses gills allowing her to survive underwater.
She appears next in Faking Miracles where she is jogging through the park. Hank spots her and runs after her, but he is attacked by some of Wide Wale's henchmen which causes her to order them to leave Hank alone. She is then seen returning home angry at what occurred at the park before going off to her room. As she is leaving, her father mentions that it is her eighteenth birthday and he is throwing her a party to celebrate.
At the party, she is obviously annoyed, prompting her father to ask what was wrong. She tells him that she didn't want a party and her father tells her he'll get her a pizza which always cheered her up as a child. The pizza is delivered by Hank, who is recognized by Sirena and her bodyguard which leads to him being chased through the building by her father's henchmen.
Later, Sirena is in her room watching TV until she spots Hank on the veranda where the two officially get acquainted until to her shock Hank jumps off the building just as her bodyguard enters and she explains she was getting air. She then looks over the veranda and finds that Hank landed safely in his hover car. He asks Sirena out on a date, and she agrees.
In It Happening One Night, Hank and Sirena go out by with Hank taking her for a ride in his hover- car and walking her through the park where they encounter a mugger (Pete White in disguise) but Hank scares him off. The two are then given directions to a restaurant by a man playing drums (Dean Venture in disguise) before they go Sirena takes a knife and removes the tracking chip her father placed on her. She tells Hank she usually does this when she is having fun which elates as he takes her out for dinner. After a few circumstances, such as bumping into an ex-boyfriend and being pursued by her and Hank's bodyguard the two go for a swim in the harbor where they share a kiss before they are taken back home by Brock and Rocco.
Sirena is Wide Wale's daughter who turns 18 in Faking Miracles. She speaks in a thick New York Italian accent, and uses profanity quite liberally. She dislikes the protectiveness of her fathers henchmen, especially Rocco, and would prefer to be left alone most of the time.
In Hostile Makeover, Hank had spotted Sirena through the use of Brock's binoculars and upon seeing her dive in a pool and look unresponsive; he attempted to save her. Upon reaching her window, he discovered she possessed gills which greatly amazed him. In Faking Miracles, she bumps into Hank at the park where he attempts to speak with her before her bodyguards attack him though she orders them off. She later encounters him at her home after he delivers her a pizza but he is forced to flee from her bodyguard. Sirena then finds Hank on her veranda where they officially get acquainted until Hank is forced to flee again. Sirena playfully asks him "What's the matter? Not willing to risk your life to go on a date with me?". In response, Hank jumps off the building and after impressing her by landing on his hover car he asks her out which she accepts. In It Happening One Night, Hank goes through great lengths to make his date with her perfect enlisting the help of his brother Dean and associates Pete White Billy Quiz-boy. While having dinner, Sirena reveals she is aware of Hank's attempts all of which flatter her as he wen through such lengths to impress her. The two later go for a swim in a lake where they share a passionate kiss before their bodyguards separate them while they gaze at each other, hinting a future relationship between them.
In It Happening One Night, it is revealed she once dated Brown Widow in his civilian disguise Jared. It is unknown how long their relationship or what caused them to break up but it appears they had a tense standing as she seemed irritated when greeting him while on a date with Hank calling him "stalker boy".
- Her name is a reference to the mythical aquatic beings called "sirens", who were purported to lure sailors to their deaths.
- Most likely due to her father's mutated DNA, she has gills on her neck and the ability to breath underwater.
<gallery widths="140" captionalign="left"> File:Sirenahank handshake.png|Sirena and Hank handshake. File:Venture hankspeech.png|Sirena on a date with Hank.