Basically the game but...

What if ROSIE was Cursa?

Some ideas:

- 682's weapon is akin to Gyomei's weapon from Demon Slayer.

-As Long as Rosie is fused to Cursa, her Hemomantic Blessing becomes Flames of HATE. Flames of HATE allows her to conjure Darkmess energy out of shear HATE.

-During the final battle, 682 IMMEDIATELY goes for the decapitation...which works!

-Until Cursa uses her Hemomantic Blessing to regenerate her head, revealing to 682 just who he decapitated.

-He immediately roars.

-[CURSA IS MY SISTER!]

-Everyone's heads turn to him as their eyes widened.

-[CURSA WONT DIE EVEN IF YOU CUT HER HEAD OFF!]

-Immediately after he gets done saying that, Cursa Immediately raises her arm, and then slams it down.

-And then all hell breaks loose as several doors appear under everyone and sucks them all in.

-682 recognizes what's going on Immediately.

-[Maribel's Hemomantic blessing...!]

-But he doesn't have any time to think. He sees everyone else falling beside him.

-He has to catch them or else they'll hit the ground too hard!

-But it seems the current team wasn't the only ones sucked in...

-...Rabbid Yoshi and Yoshi were sucked in too.

-The Final Battle has begun.