Is Magma Rex good at breaking enemies?

You don't need an elemental advantage to get good break pressure out of Magma Rex. It drains the break bar quickly even on enemies that are neutral to its element, so it keeps working in fights where you can't pick a favourable matchup.

That matters because breaking is the largest single damage multiplier in the game. Empty the bar under an enemy's health and the enemy is stunned and takes greatly increased damage until the bar refills. Against bosses that bonus is 250% more damage. A fast breaker opens that window sooner and more often, and the rest of your team does its real damage inside it.

In practice, Magma Rex earns a team's breaker slot. Its job is to empty the bar. Your damage dealers then spend the stun hitting as hard as they can.

What pairs well with it

Rookie's Bouncy Sling makes targets it hits take 15% more break damage for 15 seconds. Land it before Magma Rex starts working and the bar goes down even faster.

Mellobloom has a far higher Break stat than any other buffer. She can break alongside Magma Rex while still doing her buffing, which puts two sources of break pressure on one enemy.

Other breakers to compare

Inferlupa is one of the best breakers, has the Break combat role and a Break stat of 108. It fills the breaker slot in dark and Irisalis teams too. Minespine deals 20% extra break damage while tunneling. If Magma Rex doesn't suit your lineup, either of these can do the same job.