| "I once thought I could save the world... now look at it"
— Spoilers for Deus Ex: Mankind Divided follow!
Johnny was one of the solders under the employment of Belltower Associates during the time of the Australian Civil War, where he served in New South Wales alongside his partners Ghiradelli and Powell before being discharged.
Both of his arms and legs were replaced with alloy prostheses upon enlistment, and then some more when he was wounded in action, all against his will in order to make him an efficient killing machine, something which he had recently come to resent. He could walk through fire unharmed and kill people without leaving a trace, but could no longer feel the sand rubbing between his toes, nor could his palm feel itchy anymore despite him convincing himself otherwise. In short, Gunn does not feel "natural" anymore, and has not been able to for a long time.
Not much is learned about Johnny after he left Belltower's services except for his many marriages, all of which ended in divorce, which led him to drown his sorrows in alcohol. Even though he and Angela no longer live together or have feelings for each other, he still genuinely cares for her and upon hearing about her murder, wished her a quick, painless departure.
Deus Ex: Mankind DividedEdit
Johnny is a prime suspect in the murder of Angela Gunn in SM10: The Harvester, simply by virtue of him being augmented. Detective Karl Montag directs Adam Jensen to his apartment for questioning and try to prove his innocence.
When spoken to, Johnny will initially appear rude and sarcastic, but upon delving in further, he reveals a more emotionally depressed side due to his past and trying to cope with the fact that he is no longer "natural". His alibi cannot be initially proven due to him being by himself all night, though through a bit of investigation and/or inquiring about his past, Johnny is revealed to have had both of his hands replaced with alloy augments, meaning he cannot be the killer due to him no longer having any fingerprints.
In a twist of bitter irony, it was because he was built up to be such an efficient killer that his innocence was solidified.
- He has a Belltower jacket hanging on his coat rack and a Belltower patrol cap next to his bed.
- He has the Belltower logo hung just above his toilet and a defaced Belltower recruitment that has "Don't Stay Bottled Up" written over it.
- Gunn's apartment can be broken into before the quest becomes available. His Belltower jacket can be found hanging where it would be however he himself will not be there until Jensen comes over later for questioning.
- After talking to him, Gunn can be overheard occasionally singing the first line of "99 Bottles of Beer on the Wall."
- If Jensen mentions that he is familiar with Belltower, Johnny will mention that he looks familiar.