Legendary variant weapons - Halopedia, the Halo wiki

The Legendary variant weapons are weapons that can be unlocked in the campaign of Halo Infinite by performing various tasks. In campaign, they can be broadly divided into two categories: boss weapons, which are alien weapons acquired by defeating High Value Targets, and human weapons, which can be unlocked

MLRS-2 Hydra - Weapon - Halopedia, the Halo wiki

Halo 3 - Wikipedia

Halo Infinite ALL Legendary Weapons

Type-25 Carbine, Halo Alpha

This concept art shows how assault rifle looks without its upper shell. : r/ halo

Halo 2 - Wikipedia

Halo Infinite: Where to Find Legendary Weapons

Calcine Disruptor - Weapon - Halopedia, the Halo wiki

Weapon Variants - Halo Infinite Guide - IGN