Terrormisu, also passing off as a young lady called Tiaramisu, is an ancient demon, the final boss, and the hidden main antagonist of the Nintendo DS game Wario: Master of Disguise.
Assistance to Wario
In Episode 7, "Fouling up the Whole Works," Wario goes to Sweatmore Peak, a volcano, after Count Cannoli told him that he would meet him there. Instead, he meets a strange beautiful woman named Tiaramisu. She tells him that if he finds the Sweatmore Hotpants that he'll be able to venture further into the volcano, and tells him to be careful.
Later, in Episode 8 "When Dophins Ruled the Earth" she helps assist Wario while he is battling the tyrant of Blowhole Castle, Stuffy the Dolphin. She also helps Wario by telling him he needs a missing soul to unlock a door in Blowhole Castle.
All of this helping is entirely in vain, however. At the end of Episode 8, she states that her current power couldn't take her any further, so she ceases to assist Wario hereon.
Terrormisu the demon
In Episode 10, which takes place in Allergia Gardens, (pun on the word Allergic) Wario finds all five Wishstones, and puts them together. He is shocked, as a fully formed Wishstone reveals... Tiaramisu. She then reveals that her real name is Terrormisu, and she is a demon.
While Carpaccio is on the ground, Terrormisu repeatedly strikes him with lightning, which demonstrates that Terrormisu contains a lot of old past hatred towards Carpaccio and his family.
Goodstyle then reads the true horrific story of the Wishstone. Long ago, there was a nasty King named Poobah the Pharaoh, who, despite all his wealth wanted a wish, so he called forth Terrormisu the Demon. But the Demon called for a terrible price: The King must starve all of his people. The King agreed, but Terrormisu never granted his wish. His pyramid was sunk under the sand, as a result. Later, a sly man who is later revealed to be Goodstyle woos the Demon, and sealed her in the 5 Wishstones.
Terrormisu in battleSince Terrormisu is a demon, she is a very powerful and very formidable villain in battle. She has three forms: Sad, Happy, and Rage. It is also shown here that she is a shape shifter.
Terrormisu conjures up balls of energy in her sad form, and as Wario continues to hit her, the balls of energy last longer. Using genius form, if you don't see the red ball out of the four total balls, then she shoots some sort of explosive at you. It takes five easy hits to beat her.
Terrormisu's Happy Form shoots lasers at Wario. Three Happy faces must be shot by Cosmic Wario and they must bounce off and hit all of the heads. Spikes appear out of the ground shortly after you hit Terrormisu once. Takes 5 hits to beat this form.
This is by far Terrormisu's trickiest form. She shoots lots of fireballs at you, and causes a wall of fire to go towards you if you strike her with Dragon Wario. It takes 5 hits to defeat her in this form.
She then looses her fake face, and a more hideous face is revealed, as Wario has to strike Terrormisu one last time in order to defeat her. Terrormisu goes back to her Dimension after Wario beats her.
Terrormisu Having a Likeness for Wario?
It is revealed in the Final Special Episode, that Terrormisu, (and is hinted throughout the entire story) has a likeness for Wario.
Terrormisu's real form bares a strong resemblence to Princess Peach.