It all started as a bet, a friendly competition between the members of team RWBY to see who could kill the most Grimm in one minute.
It became so much bigger than that.
It became a symbol of hope. Uniting Humanity in a desperate struggle against those that sought to destroy everything they knew.
It became a symbol of the Past, Reminding Humanity that they were only remnants and keeping those under its banner from repeating past mistakes.
It became a symbol of the Future, signifying the peace that Humanity was fighting to restore.
But most importantly, It symbolized those who had fallen, reminding the survivors of those who had given their lives for their peace.
The rose tattoo on each and every one of them symbolized this.
This is how it came to be.