Adramelech from Monster Girl Quest, aka yeah NEVER happening, but trust me, it's a greatly thematic matchup.
Adramelech is an Apoptosis, eldritch abomonations who serves as cosmic jannies who finds paradoxes and chaos sources and cleans them out. Adramelech is the queen of the cosmic jannies then, because she proceeds to infect, hijack, and disintegrate entire universes into nonexistence. She can regenerate from being bisected with a higher dimensional slash and dropped into chaos corrosion which deletes on an informational and conceptual level (Chaos in fact is so absolute it transcends the duality of existence and nonexistence)... Just to regenerate back even stronger in Part 2. She is basically impossible to kill for good, and her goal of erasing all existence by hijacking it is so dangerous it took another high class apoptosis basically resetting everything so she never even existed in part 2... Just to appear again in Part 3.
She also has a banger music
If MGQ ever had fate treatment, maybe there's a chance way in the future, but for now, just a pipe dream matchup, like Ilias vs YHVH.