Books in Which the Protagonist Is Fused with Dorea or Has Dorea's Skills

The main character should be fused with Doria's template or have Doria's skills. There is no limit on the gender of the main character. I really like the main character who is fused with Doria. It is best if the main character's appearance changes when using skills. There is no limit on the parts that can be changed, just the hair.