Brynhildr Romantia

Brynhild Romantia: Until Death Divide the Two Apart is the "spear of love and hate" of Brynhildr. Rather than being a true spear, it is a manifestation of her deep affection and hatred towards Sigurd having morphed with the mithril spear she used in life. Due to the betrayal of Sigurd and the subsequent damage to her honor and reputation, it was used out of revenge against him.

The spear grows heavier and larger the more she loves, and is even able to kill the goddess Hel when fully grown. While its effective targets seem limited, Brynhild holds some love towards every hero due to her being a former Valkyrie. However this backfires when she uses it against Manaka Sajyou since she held entirely no love for her.

Brynhild Romantia (Passionlip)
Brynhild Romantia: Until Death Divide the Two Apart is a Noble Phantasm bestowed upon Passionlip by BB by utilizing the aspect of Brynhild within Passionlip as material, having undergone illegal modification from a normal Noble Phantasm into something with effects slightly different than the original. The more love she feels for the target, the more accurate and damaging it will become. It is said to never let her loved one escape, even should her love be completely one-sided.

Rather than manifest as a spear for Passionlip, she invokes the Noble Phantasm with her two large claws, separating them from her arms and launching them at her opponent. After they strike numerous times, they return to her, and she performs a crushing, clamping attack to finish them off. Passionlip's Trash & Crash, invoked with her hands, combines with it to create an instant-death effect as well.

Development
Although Fate/EXTRA material originally stated the illegal modification performed by BB slightly altered the Noble Phantasm's name under Passionlip, Brynhild's primary version is shown to possess the exact same name in Fate/Grand Order. Passionlip's variation was originally designed to be a "grab and throw move" where, upon locking onto the target, they were doomed. It would have increased her defense by ten times, placing her in a state of "super armor" where she would have no worries of being damaged significantly, and she would have advanced "like a heavy tank" to devour the enemy with her claws that would have morphed into the shape of lips. Upon using too much power while clenching the claws, she would have pierced through herself and dealt a large amount of damage to herself as well as the target, destroying both.