Blasphemy unto Heaven Trophy in Bloodstained: Curse of the Moon

Story related and cannot be missed.

You must beat the fourth stage, Blasphemy Unto Heaven.

Near the end of the stage is the upgrade item, a Weapon upgrade.
 

The boss of this stage is a two headed dragon named Valac. Both heads shoot fireballs, the bottom one will like to try to chomp down on you while the top one shoots these explosive purple globs. Defeating both of them will launch a second phase of this battle.
 

In lieu of a desperation attack, this time around the boss changes form and attacks from the left. This time its two heads combine into one giant head that shoots fire, and the tail at the bottom becomes a spike trap. There’s no risk of instant death if you hit them. You will need to duck to avoid the giant fire blast it spits out by moving to the platform to the right, then quickly jump back to the center platform to get maybe two hits in before repeating. Keep at it and the monster will fall.