Phase structure: Three-phase fight with cumulative pressure. Mid-fight phase rotates element or summons adds; the third phase is typically the DPS check.
Respawn rules: This boss respawns on a normal cooldown — typically 60-90 seconds after fast-traveling out and back. Loot pile rolls per kill, so it is farmable.
Element coverage: Run any element as the primary damage source. There are no flat resistances on this fight, so you have flexibility on element pick.
For step-by-step strategy, recommended Vault Hunter and a community video walkthrough, see the full Bloomreaper the Invincible walkthrough.