Falling victim of the same incident that left the half of Pinkie's body burned, Fluttershy received severe damage to her face and lungs.
Whilst being in recovery along with Pinkie while "Operation [REDACTED]" was in progress, there was no pony there to save her animal friends or her cottage. Impulsed by a similar sorrow and grief to that of Pinkie's, she decided to join the "Sol Invictus" unit formed by Rainbow, Pinkie and Rarity, being Applejack the last one to join their cause.
Fluttershy is now forced to use a mask to help her breath and talk being the later the most painful task to achieve, she decides to remain silent and let her actions speak for her…that is until she is needed to interrogate prisoners.
With no animals to make her company she decided to silence her fear and tame the beasts that dwell within the Everfree Forest to support her unit and their goal.
Stories from the battlefield tell that dying at the hands of The Kind's beasts is an act of kindness….that is, when being interrogated by her is the alternative.