Welcome to Infinite Tower

 is a Japanese-American adventure-fantasy video game series, being developed by Sonic Team and published by Sega since May 22nd, 2005.

Synopsis
Lily and Todd Fine get a job at a strange and bizarre tower that has infinite floors as they get in several bizarre adventures.

Games

 * 1) Welcome to Infinite Tower (2005)
 * 2) Welcome to Infinite Tower: Rise of the Accountant (2008)
 * 3) Welcome to Infinity Tower: Flooded

Main

 * Lily Fine (voiced by Lara Jill Miller) - a cocky and arrogant teenage girl who gets a job at Infinite Tower as she is given two explosive guns to help go through the tower and help what needs to be helped.
 * Todd Fine (voiced by Charlie Schlatter) - Lily's shy twin brother who is insecure about himself and likes making friends, being given a sword that allows him to deal with threats in the tower.

Supporting

 * The Maker (voiced by Lex Lang) - the creator of the Infinite Tower who takes the form of a snazzy well-dressed man who hires Lily and Todd to try and help bring order back to the tower.
 * Mr. Keep (voiced by [youngish yet goofy]) - a friendly and goofy android who runs an item shop which is on every floor of the tower.
 * Master Shrimp (voiced by on the first game and and Greg Baldwin afterwards) - a wise shrimp who knows all of the martial arts from Floor 2, which is a world where sea animals learned martial arts, as he allows his dojo to be used by Lily and Todd.
 * Loretta (voiced by Kari Wahlgren) - a sarcastic and jokey mechanic from Floor 3, which is just a regular metropolis, as she can upgrade Lily and Todd's weapons.
 * Sir Lionel (voiced by [noble]) - a young and brave knight who was forced to work for Cassandra due to her enslaving his kingdom as soon he betrays her and becomes the king after her banishment from Floor 167.
 * Bruiser (voiced by TBD) - a feisty and angry kangaroo from Floor 38 that can attacks anyone that dares to mess with him or his friends, quickly befriending Lily and Todd.

Antagonists

 * The Mallum (voiced by Ron Perlman) - a sinister entity of dark matter who manipulates several inhabitants of the Infinite Tower to try and lower its size due to him being banished on the highest floor of the tower, Floor Infinity.
 * Lady Cassandra Nocturne (voiced by Marina Sitris) - a flamboyant sorceress from Floor 167, which is a medieval wonderland which she has enslaved, as she forms an alliance to free the Mallum in exchange for her gaining infinite power.
 * The Accountant (voiced by Kelsey Grammer) - The Maker's younger brother who was forced to only count the floors and number them as soon he gets offered power from the Mallum after Cassandra's defeat, only if he agrees to serve him.
 * Mirror Lily and Todd (also voiced by Lara Jill Miller and Charlie Schlatter, respectively) - two evil clones of Lily and Todd from Floor 23, a floor where everything is an upside down world, who get hired by Cassandra to help her in her schemes.
 * The Gnome King (voiced by Rob Paulsen) - a megalomaniacal gnome who lives in Floor 4 as, despite his megalomaniacal tendencies, he is absolutely pathetic.
 * The Salamander (non-speaking) - a silent giant purple salamander in Floor 29 who has the ability to spit some gas at people and make them hallucinate things as a distraction for it to try to eat that person.
 * Mr. Explosive (voiced by TBD) - an insane android from Floor 12 that is capable at throwing tons of explosives at people, being recruited by Cassandra.

Common gameplay
The games play as a combat focused co-op platformer as you can play as either Lily or Todd. You are able to buy items from a shop, gain new attributes by training in Floor 2 and gain weapon upgrades from floor 3. You are given a mission board where you can go to several missions on several floors.