This one is quite a bizarre achievement, and honestly, I have no idea what exactly needs to happen in the game to get it...
Here's how I got it:

1 - Start an endless arena

2 - Select 50 random players

3 - If Troy Bonneau wasn't included in the 50 fighters, click on "search", search for "Troy", and select him, as a 51th fighter.
NOTE: If you have less than 50 fighters, I don't think it's needed to have that many. I just chose 50 for its convenience; Lots of player vs player interactions. Also, the games are short, since there's not too much players, and when Troy dies, it doesn't take too long to restart.

4 - Set the speed to 600X
NOTE: 600X is the max you can set as a "default speed" per match, you can actually make it much faster per match, but you always have to do that manually, each time a new match starts. You can do this if you have the patience to wait while looking at the game. Otherwise, 600X is fine too.

5 - Be sure to let every thing activated: Custom updates, teams, initial landmines and arena events.
NOTE: I have no idea which ones are actually needed to get this achievement, but I just want to make sure everything gets triggered so there's no risk at blocking the achievement in any way, or missing out on important steps.

Let the game run from anytime between 10 minutes to 2 hours... This one is completely luck-based.
SOMETHING will happen that triggers this, but I didn't have the patience to stare at my screen for so long and reading every single battle update... LOL

I just put it fight, and made some music for a half hour, and then I checked Steam, and I got the achievement!

Fun Fact: Troy Bonneau is the director of Triverske, the company that made this game. I guess he wanted to be in it!

GOOD LUCK GETTING IT! ! ! ! ! !