Exor

"HALT! Who goes there!? A Tresspasser! The castle now belongs to us. The Smithy Gang. This will be our first step in taking over the world. And if it wasn't for nosey characters like you, we'd practically own this world! Let's see you deal with this!"

- Exor

Exor is a giant sword-like character and a member of the Smithy Gang. Exor is actually composed of four parts, his Left Eye, his Right Eye, his mouth (which for some reason is named Neosquid), and the skull-shaped hilt (named Exor) that controls the entire body. Exor is used as an inter-dimensional gateway between Mario's dimension, home of the Mushroom Kingdom, and Smithy's dimension, where Smithy's Factory is located. Consequently, Exor can transport an infinite number of troops and weapons for the Smithy Gang, as they are held in a separate dimension, not in an enclosed space.

Super Mario RPG: Legend of the Seven Stars
Exor was a vital component of Smithy's invasion of Mushroom World. Exor, on his descent to Bowser's Keep, shattered the Star Road, breaking off seven Star Pieces, thus eliminating the power of wishes from the world. Exor crashes into Bowser's Keep, sending Mario, Bowser, and Peach (who were battling in the castle) flying to other regions of the world. The keep is occupied by the Smithy Gang, and is used as Smithy's base of operations on Mushroom World.

Mario returns to Bowser's Keep in an attempt to find Princess Toadstool. Instead, he finds a monstrously huge sword implanted in the castle. Exor claims the keep in the name of the Smithy Gang, and soon destroys the bridge linking Bowser's Keep to the rest of the world. Mario must find another way in.

Eventually, after collecting six Star Pieces, Mario returns to Bowser's Keep via a bus driver from Nimbus Land. After Mario defeats Boomer (on the chandeliers he fought Bowser on in the beginning of the game), Mario and his party are brought to the roof of the castle. Once there, Mario and his allies engage Exor. Although he wields impressive magical abilities, Exor is eventually defeated, but not destroyed. With his last ounce of strength, Exor opens his mouth, inhaling Mario and his party, transporting them to Smithy's dimension and his factory of weapons.

After Smithy is defeated, Exor dissolves into nothingness.

The iconic and recurring image of Super Mario RPG: Legend of the Seven Stars is Exor embedded in Bowser's Keep.

Many beginning players believe Exor is, in fact, Smithy. However, they soon learn the enormous Exor is only one of Smithy's servants.

Trivia

 * According to the Psychopath thoughts, Exor has astigmatism in his right eye and is blind in the left one.
 * Exor is the only Super Mario RPG: Legend of the Seven Stars boss (aside from the Yaridovich clones) that is not immune to the special effect of the Geno Whirl attack (which does 9999 damages if executed correctly).