Rut Senil Fernández Castillo, known as Rut Casfer, is a Dominican Christian singer and songwriter associated with Santo Domingo. She has recorded as a guest of En El Cielo Worship and works with Darwin Jiménez in the project «Rut & Darwin».

Early recordings

In 2021 she was the featured vocalist on «Amor Sin Condicion (Cover)», a worship recording released by En El Cielo Worship through «Camila Studio». The recording connected her voice with the congregational repertoire developed by the Santiago ministry.

Rut & Darwin

In December 2024 «Rut & Darwin» released «Deseable» with «HONOR A Ti». «El Vendrá» followed on May 16, 2025, with «HONOR A Ti» and «EbenezerMC» also credited as artists. The song, about the return of Jesus, was written by Ruth Fernández and Darwin Jiménez; Diógenes Mercedes produced the recording and shared its arrangement with Danny Ventura. That year the duo also appeared on «Ulalala» with Propiedad de Dios.

Legacy

Rut Casfer has moved from guest performance to collaborative songwriting. Her recordings with En El Cielo Worship and «Rut & Darwin» show two aspects of her work in Christian music: congregational worship and songs created with other musicians.