Firebrand can light Torches and can be used offensively against enemies in battle. Some enemies like Glurps or Spiky Snifits have a weakness to the Firebrand, and in a few cases, they can only be damaged by it. Other enemies (like Bowletta's normal form or the Beanerang Bros.) get healed by it instead. They can also use the Fire Bros.Bros. Attack, which involves Mario flinging fireballs at Luigi, who then launches them at the enemy with his hammer (in the remake, Mario rapidly tosses fireballs into the air to create a huge fireball before Luigi launches it towards a single enemy with his hammer). A more powerful variant is Super Fire Bros., however using it uses up more BP and (may) need Mario to use Syrup more often. Here, Mario can create a huge fireball when Luigi hits smaller fireballs back at him, and once the attack ends, Mario bounces off of Luigi to spike it at the enemy for more damage and possibly inflict the Burn status (in the remake, Luigi hits the huge fireball upwards so Mario can spike it, and it also creates a shockwave which damages other enemies).
* Exclusive to Mario & Luigi: Superstar Saga. • ** Exclusive to Mario & Luigi: Superstar Saga + Bowser's Minions. † Enemy, boss, or stat exclusive to the main game. • †† Enemy, boss, or stat exclusive to Minion Quest: The Search for Bowser. • ††† Enemy variants differ in Mario & Luigi: Superstar Saga + Bowser's Minions.