PH
Rimuru unleashes his "Endless Demonic Manifestation of the Primordial Chaos with Omnipotent Control of Creation and Destruction" ability, causing a massive black hole to form, sucking in everything in its path.
Yuno counters with her "Absolute Divine Authority over the Fabric of Reality with the Omniscient Power to Rewrite Destiny and Fate" ability, creating a new reality where Rimuru's attack never existed.
Not to be outdone, Rimuru uses his "Supernova of the Endless Multiverse with the Power to Manipulate Time and Space on a Cosmic Scale" ability, causing multiple universes to collide and merge into one massive entity.
Yuno responds with her "Infinite Blade Dance of the Time-Space Continuum with the Ability to Control All Forms of Energy and Matter" ability, creating blades of pure energy that slice through Rimuru's attack.
With their abilities evenly matched, the two stare each other down, waiting for the other to make their final move.
Rimuru charges up his ultimate attack, "Primordial Annihilation of All Existence with the Power to Erase Anything and Everything from History", but Yuno counters with her own ultimate attack, "Cosmic Rapture of All Creation with the Power to Ascend Above the Highest Heavens".
The two attacks collide, creating a massive explosion that engulfs the entire universe. When the smoke clears, only one person is left standing.