After her journey of spreading the world of the Storm King’s fall, Tempest Shadow returned to Equestria, just around the time it was decided that Princess Twilight Sparkle needs to have her own guards and she specially wanted Tempest to be the captain of them.

There wasn’t any objection from Celestia and Luna, they knew Tempest was great for the
position after leading the Storm King’s army for years. Tempest was hasitant to take
the position at first, as she felt she didn’t deserve this amount of trust after what she
done, but in the end she took it, so she could repay Twilight’s kindness towards her.

The guards under her said she was rough around the edges, kinda awkward to talk
to and sometimes even kinda terrifying, but in the end a fair and great captain.