Millium Orion is one of the new characters in the Cold Steel trilogy of the Trails Series. A young girl accompanied by her puppet Airgetlam, who is actually a member of the Ironbloods, the Chancellor's personal information agency under the code-name “White Rabbit”. At first debuting as a support character, she become a playable Class VII member as the game progresses.
Millium has a shade of blue-to-turquoise short hair and amber eyes. She wears her special-ops jumpsuit which is waterproof and paletted in the same color as Airgetlam. Later on in Trails of Cold Steel, she later wears the standard Class VII crimson uniform with a dangling beanie after her transfer.
In Trails of Cold Steel II, she switches to her wartime clothes styled as a sailor uniform with a beret. She wears a long-sleeved monochrome shirt with a belt around her chest styled like a ribbon, with a thin black shirt and brown shorts on the inside and wearing dark turquoise patterned stockings in white boots
In Trails of Cold Steel III, Millium travels around in her new intelligence uniform with a new beret. black-striped stocking with white boots
Millium has an innocent and friendly personality, and her classmates and friends are often surprised about how she speaks of such confidential information so lightly.
Despite this, Millium lived an unusual life being used as a tool of sorts due to her being an Ironblood and never able to cry or otherwise normally express emotion. She joins Class VII, but sometimes feels she does not really fit in. She never attended Sunday School and is ignorant in some ways of the normal lives of people. It is later revealed that she is actually a "manufactured human" of advanced technology, which explains why there is no change in her status despite aging.
- She joins the Cooking Club at the Academy.
- In Chapter 4 of Trails of Cold Steel, it's revealed she's phasmophobic.
- Millium shares the same position as Crow Armbrust as to joining the Class VII dormitory.
- Her bonding trophy in Trails of Cold Steel is titled "The Young and the Reckless", which is also a reference to the long-running soap opera, The Young and the Restless.
- Her bonding trophy in Trails of Cold Steel II is titled "One in a Millium", a joke on the famous saying "one in a million".
- Millium's room in Class VII's dorm is full of Falcom references. She has dolls of Noi from Nayuta no Kiseki and the penguin from Zwei II.
- Her name "Orion" has several etymologies upon her character and her primary affiliation.
- Orion is the prominent constellation visible throughout the world, named after Orion, a hunter in Greek mythology.
- All the Ironbloods (plus Chancellor) are somehow referenced from The Wizard of Oz. In both Millium and Altina's case, the last syllables in their last name is "rion" ("Lion").