Sonia Strumm, known as Misora Hibiki (響 ミソラ, Hibiki Misora) in the original version, is a character in the Mega Man Star Force series of RPG games and the seventh sub-series in the Mega Man franchise. After fusing with the FM-ian Lyra, she is known as Harp Note; this form is somewhat considered to be the Star Force series' counterpart of Roll. She is renamed Sonia Sky and Lyra Note in the localized version of the anime.
In terms of demeanor, Sonia is quite the opposite of Geo: spunky, outspoken, and mischievous. Sonia seems to be romantically interested in Geo, shown by the fact that she has asked him out on dates several times. Sonia also throws herself in front of one of Queen Ophiuca's attacks to protect Geo, and as a result is poisoned. In the second game, Sonia again asks Geo to go to Wilshire Hills. In this game, Sonia seems more blatant about their relationship. She once asked Geo who he likes better between an argument with Luna. She has also shown jealousy when Geo is with a girl alone during his mission of finding the OOPArts.
Sonia is a popular rock star of fifth grade age who, like Geo, is depressed over the loss of a parent, her mother, which leads them to establish a friendship. Sonia is constantly pressured by her money-starved manager, leading Lyra to manipulate her into transforming into Harp Note and attack people throughout the city.
In Mega Man Star Force 2, Hollow blackmails her into working for Vega in exchange for Geo's safety. When MegaMan finds her in the Bermuda Maze, she claims that she doesn't want to be found, and cuts off their Brother Band. Later, when MegaMan is lured out by Hollow and Solo, Sonia rescues him and transports him back to Echo Ridge. When Mega Man goes back to the Bermuda Maze, he defeats Sonia. There, she explains she was following Vega's orders to protect to which Geo replies how her betrayal did not protect him. She also helps Mega Man find Mu's location in the Bermuda Maze afterwards. In the third game, she is officially allied with the Satella Police and is registered under Project TC - a registry of those who are allowed to legally perform Wave Change - as No. 004. She also is an actress and appears on a TV drama.
Lyra, known as Harp (ハープ, Hāpu) in the Japanese version, is based on the constellation Lyra. She is an FM-ian who used to work for the FMian king and often hides in Sonia's guitar. Her form is a cross between a harp and a note. She is shown to act like a high status old lady, whom gets into arguments with Omega-Xis. When she first met Sonia, Lyra tries unsuccessfully to invade Sonia's heart, so is forced to take control of her while she sleeps. Following her defeat by Mega Man, Lyra becomes an ally of Omega-Xis.
- The name Sonia is derived from the Greek name Sophia, meaning "wisdom." In Hindi, the name means "golden" and "beauty". Strumm has no real meaning, but is pronounced the same as the word strum, the act of brushing one's fingers over the strings of an instrument.
- The name Hibiki Misora may be a reference to the late Japanese singer and actress Hibari Misora (1945 - 1971). The word Hibiki (響) means echo or resonance in Japanese.
- Sonia is the only Star Force character who has cut her BrotherBand with Geo twice (first when Geo was confused after his battle with Gemini Spark, and again when Sonia wanted to protect Geo while she was working for Dr. Vega).
- Sonia's seiyū is Misato Fukuen and her English voice actress is Wendee Lee. Notably, all of the songs sung during the anime are sung by Misato Fukuen, and twice, once during the anime and once during the games, Misora Hibiki is portrayed actually singing the theme songs, the latter case done through printed vocals.
- If the player looks inside Sonia's Transer, they will see that she has a Harp Note battle card, even if this is done before Lyra is introduced in the game (this also happens with the other bosses even before they were controlled by their respective FM-ians).