Vexcalibur

The Vexcalibur is a Void Exotic Glaive introduced in Season of Defiance. Its intrinsic M1R Distribution Matrix fires a spread and has a quick-draining shield; blocking damage grants Void overshields to you and nearby allies. A second perk, Perpetual Loophole, boosts melee damage while shielded. It is a rapid-fire glaive.

Acquisition

Original quest, per PCGamesN (requires Lightfall and the season):

1. Find the glowing Vex energy ball in the Gulch of the European Dead Zone and investigate the digital trace.
2. Collect six more digital traces in the EDZ, each within a short window, to unlock the cave access code.
3. Complete the //node.ovrd.AVALON// Exotic mission (1800+ Power recommended).
4. Visit the War Table at H.E.L.M. to analyze the findings and receive the weapon.

First completion guarantees a Deepsight Resonance drop, so the weapon can be crafted.

Catalyst

Three catalysts (Immovable Refit, Robber Refit, Feedback Refit) drop from the boss on Legend difficulty runs of the mission, one per run. Immovable: stationary ranged damage with shield up builds energy; Robber: melee final blows reload from reserves; Feedback: blocking damage partially reloads from reserves. Sources spell the names slightly differently.