|Real Name||Alexander Maxwell Nox|
|Alias||Dr. Mikhael Caustic|
|Relatives||Arthur Rutherford Nox (father, deceased)|
Katerina Tikacek Nox (mother)
Tae Joon Park (step-brother)
|Voice Actor||JB Blanc|
Alexander Maxwell Nox, otherwise known as Dr. Mikhael Caustic and most well known as Caustic, is a Legend first introduced at the launch of Apex Legends. A murderous chemist, he entered the Apex Games to test his deadly gases on living subjects.
Alexander Maxwell Nox was born on February 25, 2685 in Hollygrove, Gaea to Katerina Ticacek Nox & Arthur Rutherford Nox. Nox was a spoiled child growing up,  and he eventually went to work at the pesticide manufacturer Humbert Labs in Zaldana City, working as a research assistant under Dr. Franklin Humbert. Eventually, Nox began to test his gases on human subjects in secret. 
In 2723, Humbert discovered Nox’s experiments, leading to a confrontation between the two. In retaliation, Nox murdered Humbert and burned the laboratory to the ground. To cover his tracks, he severed two of his fingers and placed them near the charred, dismembered corpse of one of the victims of an experiment of his several weeks prior.  He departed the lab with a grappling hook through the ceiling. This incident was witnessed by Pathfinder, who was working as a window washer at Humbert Labs. 
The investigation was overseen by the Gaea Global Task Force, with senior forensics director Dr. Francisco Trejo, chief medical examiner Dr. Tamara Griffin, and lieutenant Victor Maldera. Based on the evidence, Trejo and Griffin moved to close the case. Maldera, however, objected, and soon became obsessed over the case. 
Later on, Nox was involved in an infamous prison break. Witnesses took note of the toxic gases used in the altercation. 
After the incident at Humbert Labs, Nox crafted a new identity under the alias of Dr. Mikhail Caustic. As a part of his facade, he claims to have been born in 2690, graduated from college with a PhD in 2720, received the Heinrich Hammond Award for Excellence in Science in 2725, and took a sabbatical on Solace at an unspecified date.  Continuing to research his gases, he entered the Apex Games, where he could test them on living subjects - leaving a considerable trail of bodies in his wake. However, his disguise was a fragile one - his mother, watching an Apex Games match, was able to see right through it, with the only noticeable difference to her being the part in his hair. 
One day, Nox was confronted by Angela Fazia, a reporter for the Outlands Journal tabloid, regarding the prison break. Feigning offense at her accusations of involvement, he insulted her and moved on with his day.  
At some point, Nox allegedly held a tenure with Vinson Dynamics. However, whether or not this is another part of his facade as Mikhail Caustic is unknown.  He additionally submitted an application to become a simulacrum after his death. 
One night in the city of Malta, Psamathe, Maldera encountered Pathfinder after the latter accidentally murdered the customer of a local restaurant. Taking the MRVN as evidence, he found video evidence of the arson of Humbert Labs, proving Nox’s survival. Maldera returned to his hunt for Nox with renewed vigor.  He was later reassigned to the case. 
The Broken Ghost
After Loba joined the Apex Games, she solicited the assistance of the other Legends (sans Revenant) to hunt down pieces of an artifact on an alternate Kings Canyon, in the Shadowfall dimension.  Nox, however, decided to act as a mole and feed information to Revenant in an obsessive, overprotective attempt to keep Wattson and Crypto away from each other. 
Early into the hunt, Wattson is injured during a sortie in the Shadowfall dimension. Nox stayed at her bedside during a majority of her recovery - much to the surprise of the other Legends, not expecting the seemingly uncaring Nox to be the one to hold vigil. When Loba callously brushes off her injury, Nox attacks and threatens her. 
Immediately after, Revenant arrives and reveals that there is a mole amongst them, sowing distrust.  He eventually returns, this time in the guise of Crypto’s seemingly unhackable drone.  Caustic seizes the opportunity to frame Crypto, citing his hatred for the Mercenary Syndicate - as both he and Revenant seek revenge against the Syndicate for their own respective fates, it would make perfect sense for them to work together. Crypto rebuts, but the damage is already done. 
Soon after, Nox is confronted by Gibraltar. He shamelessly admits that he is the mole, citing his wish to keep Wattson and Crypto apart, as well as his anger at Loba for digging into everyone’s past. The pair’s ideals clash, with Nox confident that the Legends’ trust has been severed, and Gibraltar resolute that they will come together again. 
One Saturday in 2733, Nox completed an Apex Games match on Kings Canyon. After the match, he met with an individual wearing a hazmat suit, obtaining a bag of bloody meat and departing for a hidden laboratory somewhere in Solace City. He then conducted experiments with starved Prowlers, only to be discovered by Wattson and Rampart. After a brief skirmish, the prowlers were freed and began to rampage through the streets of Solace City. 
After the Solace City hospital was destroyed by a crashing aircraft, Nox assisted in fending the Prowlers away from the wreckage. 
While Pathfinder is gathering information regarding his creators from Crypto, Nox angrily charges into the latter’s residence, infuriated that Wattson is ignoring him. Crypto traps him using his home security system, but he is released by Pathfinder’s naivete. The two argue, and Pathfinder correctly deduces that the two are step-brothers. 
Season 8 Launch Trailer
Nox later obtains clearance from the Mercenary Syndicate to construct a chemical treatment plant on Kings Canyon to extract fuel from the wreckage of the IMS Thermopylae, which was quickly leaking into the Duchess River.  However, his true plan was far more sinister - wishing for a larger sample size than the Apex Games, Nox sought to create enough chemicals to attack Solace City. He is confronted by Wattson, whose pleas he ignores in favor of the data he would gather. He unleashes his gases on her in retaliation, but when she collapses, his facade breaks, and he rushes in to save her. Wattson electrocutes him, putting an end to his plans. She tells him that he will have to earn back her trust from now on.
Wattson agrees to not inform the Syndicate of Nox’s plans, on the condition that he works to become a better man. She additionally questions him about his coughing fits, demanding that she deserves the truth, but he responds that it is none of her concern. 
The Legacy Antigen
After the outbreak of the Medusa epidemic on Olympus, Nox is elated at the idea of watching hundreds of people die. However, this illusion is shattered when Crypto informs him that Mystik, their mother, is one of the patients infected.  After verbally sparring with Crypto, an irate Nox agrees to help, directing the Legends to the Carthage spider, an arachnid native to Gaea that contains an agatoxin that can fight the Medusa disease. 
The Legends depart for Gaea on a ship flown by Fuse, with Nox taking the opportunity to mock him for his earlier confrontation with Maggie.  He reluctantly pairs up with Crypto for their trek, where the latter asks why he hid himself from their mother for so long. Nox responds that he has a terminal cancer diagnosis, and he was supposed to be dead by that point. Before he can continue, the two are captured in a den of Carthage spiders. 
After waking up, the two find themselves bound alongside Loba and Valkyrie. Nox breaks free using his hammer, intent on fleeing with his own captured spider to create a cure for his cancer.  He reluctantly frees Crypto as well, stating that someone will need to take care of their mother when he is gone. He continues his attempt to take a spider for himself, but Valkyrie punches him for this. 
The Legends return to Olympus, where the chemicals from the spiders are able to heavily contribute to the cure, stopping the epidemic. A doctor approaches Nox and Crypto, stating that family members will be allowed to visit a recovering Mystik. As payback for her care for him, Crypto allows Nox to go in his stead. Seeing his mother after so many years, Nox and Mystik have a heartfelt reunion. 
Returning home, he finds a letter waiting for him, declaring that his application to become a simulacrum after death has been declined on the grounds that his mental health screening returned less than positive results. Late that night, he hears a knock on his door, finding a box on his doorstep containing the captured Carthage spider he intended to use as a cancer cure. It had been left there by Wattson and Crypto, with the former hoping that he can become a better person.  Whether or not he was able to cure his cancer is unknown.
|In-Game||Videos & Trailers||Online Media||Publications|
Quest side stories
- Caustic has cancer at a stage that he himself considers as incurable. Before the confirmation in "The Legacy Antigen", it had been hinted through a voice line, where he says he has faced his death, right before going into a hacking fit.
- His global identification number on Gaea was ARN0-225P-ER9.
- Notably, the first three letters could indiciate his father's initials, and the first four numbers are his birthday. The rest of the code is unknown.
- Despite using an alias in the Apex games, Jacob Young, Director of PR for the Mercenary Syndicate, refers to him as "Nox".
- The case file on Gaea indicated Caustic was diagnosed by multiple medical practitioners as a "confirmed sociopath." The term is outdated and widely considered an ableist synonym for a person who has Antisocial Personality Disorder (ASPD).
- This, or possibly other psychological issues, resulted in the rejection of his self-applied application for being turned into a simulacrum. 
- In the discussion getting Revenant into the Apex Games, Caustic was discussed as having gone soft since some girl joined the games, most likely Wattson. 
- As explained by writer Tom Casiello, the Nox Gas is a corrosive gas, that eats through clothes, skin, and metal, unless countered by a chemical compound only he possesses so it doesn't affect him, which explains why the gas still affects Pathfinder, Bloodhound, Revenant, and Ash.
- His gas contains agatoxins from Carthage Spiders, a mammoth class arachnid found on Gaea that emits toxic gas from its abdomen. The agatoxin is similar to the Medusa virus. This was referenced in his death certificate long before he confirmed it himself in "The Legacy Antigen."
- According to Manny Hagopian, Caustic's name was originally supposed to be "Alexander Gaskins" based on the serial killer Donald Henry Gaskins. It was changed to "Nox" after it was pointed out that "Gaskin" has the word "gas" in it and Manny agreed it felt weird.
Caustic's voice actor, JB Blanc, has portrayed a variety of roles, including:
- Extra Stories - Death Certificate
- Out-of-game media - Reflections
- Stories from the Outlands - Fight Night
- Loading Screen - Blackheart's Rage
- Pathfinder's Quest Chapter 9 - "Oh Brother, Where Art Thou?" Cite error: Invalid
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- Season 5 Quest - The Broken Ghost - Chapter 5 - The Lying Liar
- Out-of-game media - The Legacy Antigen Epilogue
- Out-of-game media - Hammond Break-ins
- The Broken Ghost Prologue - "The Duplicitous Snake"
- The Broken Ghost Chapter 8 - "The Unwavering Protector"
- Season 5 Quest - The Broken Ghost - Chapter 2 - The Detached Chaperone
- Season 5 Quest - The Broken Ghost - Chapter 3 - The Liberated Narc
- Season 5 Quest - The Broken Ghost - Chapter 6 - The Oblivious Mole
- Season 5 Quest - The Broken Ghost - Chapter 7 - The Shattered Spirit
- Overtime Issue 3
- Overtime Issue 4
- Season 8 Launch Trailer
- Armageddon Page 1 - "Armed and Dangerous"
- A Shock to the System
- The Legacy Antigen Part 3 - "She Blinded Me With Science!"
- The Legacy Antigen Part 4 - "Getting the Band Back Together"
- The Legacy Antigen Part 5 - "Haunted By Broken Ghosts"
- The Legacy Antigen Part 7 - "The Terrible Truth About Alexander Nox"
- The Legacy Antigen Part 8 - "Abandonment Issues"
- The Legacy Antigen Part 9 - "Retribution"
- The Legacy Antigen Part 10 - "Legacy Found"
- Manny Hagopian on Twitter