Demon Paladin

The moment her vision faded, the pain exploded within Sheila's body, yet it felt different. Rather than her body being damaged, she felt like the remnants of Lumina's power were being destroyed and used to fuel her transformation. 

A dark yet holy energy. 

[You will become his paladin using that woman's divinity as the cost. I shall give you mine.]

[Serve the King with all your body and soul—seek his forgiveness through bloodshed!]

[Arise, First paladin of the True Demon King.]

Sheila's body almost shattered. The moment she heard Serena's harsh yet fair voice, her muscles expanded, tore apart and reformed. 

Every inch, speck and millilitre of inferior muscle, flesh and blood was burned, destroyed or removed in this way, as piece by piece, the goddess of darkness reforged and created the perfect body for Sheila to serve her penance in.