For those who have not completed games in the Xenoblade Chronicles series, this page contains spoilers regarding the plot. Discretion is advised.
During Alien Nation, he asks the player to get three uneducated Ma-non for a human-customs seminar, after all the Ma-nons are recruited, he is revealed to have a genocidal hatred for alien races due to the destruction of Earth and depending on the player's choices, he will or will not execute three innocent Ma-non citizens for the sake of humanity. If it is decided to stop him from killing one of the three Ma-non citizens, he rides the Lineage, a level 33 Skell, and will be accompanied by three level 22 BLADE members.
After his defeat, he escapes and forms an anti-xeno militia with other like-minded BLADE members. Eventually Cross is sent by Eliza and Alice to negotiate with him to avoid further violence but fails and is defeated again. Later, Alex sends a Sniper to kill activist Eliza for her pro-xeno stand but only manages to damage her and is eventually rounded and defeated by Cross.
In Alex's Last Stand, Alex is found again at Kw'arah Cloister in Cauldros. This time, he is working with the Ganglion for his own agenda but is defeated and badly wounded, however, before dying, he kills DV482: Duvel, a surviving and deranged Definian with him claiming that he has no regrets for his past actions.