Summon Night: Twin Age was the first Summon Night game to be released on the Nintendo DS.
During the upcoming days of Aldo and Reiha's "Coming of Age" ceremony and Princess Ayn's ritual to become accepted as the Spirit King's daughter, a new havoc has begun that has brought all spirits in disorder. In order to find the cause of this, the two protagonists seek out to find the answer. And find more than they have intended.
Gameplay and system
The game's control revolves mostly on using the stylus and the touch screen, such as tapping or dragging on an empty space for movement, as well as tapping to select options or furthering dialogue, although dialgoue can still be furthered using the "A" or "B" buttons. Combat is also touch screen oriented, which requires the player to tap on enemies to attack or by holding or drawing lines for certain chracter skills and attacks. You can use 3 characters in battle at one time, which are the main heroes and an additional AI controlled ally, however you're unable to switch them until you are on the map screen. You can switch between the two main characters for use in battle, in which the idle character will be controlled by the AI. You are forced to use the other main character if the one you are using is knocked out. If both player controlled characters fall, but the third unplayable partner is still alive, you would still get a game over.
Aldo: A melee oriented fighter. He is able to use swords, axes and spears with ease. He has a good defense, offense and HP, but he is weaker in magic defense. He is Reiha's little brother and is a glutton for Banna berries. Later in the game, he is revealed to be a Summon Beast, who was summoned by Reiha.
Reiha: A talented magic user. She is a powerful user of summoning and spirit user. She has a lower HP but makes up for her great SP guage. She is an older sister to Aldo and is a great cook herself.
Nassau: A Kascuza who lost his parents due to an invasion by humans, which caused him to have a strong resentment towards human summoners. He's a good axe-wielder and has strong wind spells, as well as having a higher HP but at the cost of a lower SP. A good choice if you like to have an equal balance to the team. He develops a crush on Reiha, later on in the game if you choose correctly.
Ayn: A young Kascuza priestess, also known as "Princess Ayn". She's a staff user, a great healer and a user of water magic. Has a higher SP, but lower HP. She has a little crush on Aldo if you choose correctly early on in the game.
Ticah: An apprentice summoner. She loves to sing to people, children, and even Reiha/Aldo if you have a nighttime chat with her. She uses her bow and arrows as a weapon, and she has different songs for stats raisers such as for magic, much like Reiha, but she lacks attack magic. She also developes a slight crush on Aldo as time goes by. She leaves for 2 chapters towards the end of the story, but returns eventually.
Mardin: Reiha's uncle, as well as her guardian. He may seem as a strict person at first, but has a soft and caring side as well. He can use spells and such, but he uses fist-type moves. He is also an ex-summoner, who was respected for his abilities.
Lila: A young woman, who is also a learning Summoner teamed up with Arlus. She is quite strict, but is also very kind at times and considerate. Lila is also quite talented with drawing. Her favored weapon is the spear, and she has a few spells. Lila strikes slight balance between Reiha and Aldo. Getting to know her as Aldo throughout the game makes her develop romantic feelings for him.
Millisar: A summon beast with a cold tsundere attitude. He doesn't like Aldo and Reiha at first, especially Reiha since he nearly beats her up after he met her a couple times, but he eventually comes to care for them. He can have a crush on either Aldo or Reiha basing on who you choose. He carries his dao with him as a weapon, and has the same dark spells as Reiha. Millisar is a good choice for defeating enemies quickly, as he's quite efficient at hacking them to pieces.
Nemo: The storekeeper of Dolphin Song. He is also known to be quite helpful at times in this store and sometimes annoying.
Triplet Store-keeper sisters: One of them is the Summon Night know-it-all and will give you valuable hints and help to the game, another is the store-keeper/clerk. The last is the one who talks to you through out the storyline. She sometimes would requests favors from you.
Saffron:A young woman who is training to be a summoner. They meet up with Aldo in Reiha when they try to reach Mardin. She asks for some favors or tries to get you to find Callaway for her.
Callaway: A young man training to be a summoner. They meet up with Aldo and Reiha when they try to find Mardin. He is often lost and sometimes asks you for favors, or Saffron asks you to find him.
Ingiell: The elder of Marbado, he is Nassau's grandfather and the head priest. He is the one who took in Reiha and Aldo to take care of them for safety.
Arlus: A young man who is becoming a summoner. He says "I'm the Golden Arlus" but really he's an embarrassment.
Phicra: A summon beast with angel wings. She has a motherly atmosphere to her and plans to set summon beasts free. However, in the end she is unable to reach her goal. Millisar looks up to her with respect and she is like a mother to him.
Agneah: A young summon beast who appears during the final chapters and loves picking on the main characters. In the end, she joins up with Arlus to go on an unknown adventure.
Ghardib: A huge brutal red summon beast. He betrays Phicra to try to destroy the world. Reiha and Aldo stop him, of course.
Zarahm: Ticah's uncle. He keeps contact with her on a cellphone. He is also her teacher, and was once known far and wide as a great summoner, but this changed toward the end...
Talij: The Summoner Magistrate. She is known as 'Talij the Cold'. She is a skilled summoner, but nothing is really known about her.