BattleTech: Legends: Test of Vengeance by Bryan Nystul

ON THE FRONT LINES...

The warrior Clans created the Elemental to be the ultimate infantry soldier. Genetically engineered to be bigger, stronger, and tougher than mere humans, and equipped with advanced power armor, Elementals can stand toe-to-toe with BattleMechs. Among this elite breed, young Jake Kabrinski is a fast-rising star who has never known defeat.

The Draconis Combine and Clan Ghost Bear, bitter enemies during the Clan invasion, have coexisted in peace for a decade. But that peace is shattered when a renegade faction of the Combine military invades the Ghost Bear capital of Alshain. Honor demands a reprisal, plunging both powers into a brutal conflict. On the front lines, Jake will learn his toughest lesson: Some enemies cannot be bested...