Snowbird Saga

Taking place in the Battle Tech universe, the Snowbird Saga is the tale of a mercenary unit fighting the Clan Invasion. When her father recognizes that the Sentinels need a unit specifically to fight against the Clans, Sheila Arla-Vlata rises to the top of the candidate list for leadership of the Snowbird battalion. First story is found here.

Relevant tropes:
 * Action Girl: Quite a few, starting with Sheila herself.
 * Awesome McCoolname: An astounding number. Chuck Badaxe is a good place to start.
 * Badass: Quite a few of these tropes
 * Badass Boast: "My name is Lance Commander Marion Rhialla. I have drunk more beer, pissed more blood, screwed more people, and killed more Mechwarriors than all of you combined. I am fifty-two years old, tired, and I hate everyone. Especially nobles."
 * Badass Crew
 * Little Miss Badass: Maysa Bari
 * Boisterous Bruiser: Tooriu Kku
 * Defector From Decadence: Senefa Malthus
 * Drill Sergeant Nasty: Marion Rhialla during Snowbird's Interlude.
 * Improbable Age: Most everyone thinks Sheila's father is crazy for giving a battalion command to a nineteen year old. Maysa Bari is an even better example, being only sixteen as of Snowbird's Interlude and already has eight solo kills.
 * Mama Bear: After catching a saboteur who had gotten Sheila captured, many of the older female members of the Snowbirds (who helped raise Sheila) subject the man to Cold-Blooded Torture to make him talk.