He debuted in DOA2, replacing Bayman and was nothing more than a clone of him (Bayman was brought back in a later re-release). As the series progressed Leon became more and more unique, until by DOA4, they were both very different. They still shared a few moves, but were nothing alike.
Leon was a safer, more offensive character. And his brutality was just awesome. His Desert Falcon air throw, his headbutting tackle throw, and his 4 part combo throw that ends with him swinging his opponent by their leg and tossing them across the stage are all great fun to watch.
The funny thing is that, for mysterious reasons, in the first release of Doa2 TN decided to substitute Bayman with Leon and the negative response of the fans led them to bring back Bayman. Nowadays is happened exactly a similar thing but this time with the same Leon victim of it XD
haha and now they are both back!! leon seems like huge fun, i am definitely gonna use him. momiji too...she just seems like she'll be a good character for me too. i will main bass always, but i love how, for the first time, there is a fighting game where i actually want to use just about every character.
http://www.youtube.com/watch?v=JE-vI85zkR8