Rev. Leslie Takahashi

Lead Minister

Rev. Leslie Takahashi has served the Mt. Diablo Unitarian Universalist Church as a minister since 2008. Passionate about the ways a vibrant and aware community can help people reawaken to the life of the world, she is also engaged in work to ensure that our communities serve all it citizens.  Using her background in leadership development, economic development and education policy and nonprofit management, her goal is to empower others to take leadership. She is the co-author, with Chip Roush and Leon Spencer, of The Arc of The Universe is Long: Anti-racism and the Unitarian Universalist Association (Skinner House 2008) and a contributor to a number of professional publications and meditation collections. Finding Unitarian Universalism in her twenties, she has served extensively at the congregational, District and national levels both within the Unitarian Universalist Association and the UU Ministers Association. Her family, especially children Garner and Liam, offer on-going inspiration. Send email to

David Usher

Rev. Dr. David Usher

Acting Associate Minister

Rev. Dr. David Usher joined Mt. Diablo Unitarian Universalist Church as Associate Minister in the summer of 2016.  A life-long Unitarian born in Adelaide, Australia, Rev. David has been in ministry more than 30 years.  He has traveled extensively. In addition to several ministries in the UK, most recently for seven years as District Minister for Unitarians in London and the Southeast of England, he was founding president of the International Council of Unitarians and Universalists from 1995-1999, and served as Consulting Minister with the UU Fellowship in Paris, France.

No stranger to the US, Rev. David also served a UU congregation in New Hampshire for nine years, and two years as Interim Minister in Grass Valley, CA.  Rev. Usher studied for the ministry in England, and has two degrees in philosophy and theology from the University of Oxford.  He also has a doctorate in ministry from Andover Newton Theological School in Boston, earned during his time in New Hampshire.  He has published two books, Twelve Steps to Spiritual Health, and Life Spirit, and is presently working on a third book, Life Lessons.  He now lives in San Mateo.

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Ranwa Hammamy

Acting Assistant Minister

Ranwa earned her Master of Divinity degree at Union Theological Seminary, where she focused on Interreligious Engagement. She serves on the Steering Committee for DRUUMM (Diverse & Revolutionary Unitarian Universalist Multicultural Ministries), and was a facilitator at the UUA’s Multicultural Leadership School for youth and young adults of color. During seminary, Ranwa served as a Lead teacher with the children’s religious education program at the First Unitarian Church of Philadelphia, where she created a story-based interfaith curriculum called “Patchwork.” A self-described “UU-Muslim,” Ranwa hopes to serve both living traditions in her ministry. She is also a classically-trained vocalist, cat parent, and lover of children’s books. Send email to

Jim Lewis

Intern Minister

Jim recently graduated with a Masters of Divinity from Starr King School for the Ministry in Berkeley, CA.  He has served UU churches as Director of Religious Education in Petaluma, CA and music director in Springfield, MO.  Outside of the church, he was an elementary school music teacher for nine years in Kansas City, MO as well as facilitating large group conversations about countering oppression with high school students.  Jim lives with his husband, Derron, and spends his free time playing video games and watching the cartoon Steven Universe. Send email to

Religious Education & Programs


Mr. Barb Greve

Developmental Director of Lifespan Religious Education

Mr. Barb Greve serves as Developmental Director of Lifespan Religious Education at the Mt. Diablo Unitarian Universalist Church in Walnut Creek, CA. Barb earned his Master of Divinity dgree at Starr King School for the Ministry and is a UUA Master level Credentialed Religious Educator. Barb has served as interim director of religious education to congregations in Atlanta, GA, Newton, MA and Hamden, CT. Prior to seminary he served in the UUA Office of Bisexual, Gay, Lesbian, and Transgender Concerns. Barb is the co-founder of Transgender Religious professional Unitarian Universalists Together (TRUUsT) and a tri-founder of the Guild of Interim Religious Educators (GIRE). Additionally, he is a trained Our Whole Lives (OWL) facilitator. Barb is a lifelong Unitarian Universalist and the child of a Director of Religious Education, a lapsed classical bassist, former home brewer, and a lover of Legos. Send email to


Marena McGregor

RE Assistant/ Childcare Coordinator

Marena earned her Bachelor of Arts in musical theatre with a minor in music from California State University East Bay. She has been an active participant and employee in the RE program for over a decade. Marena has worked as a caregiver, RE teacher, Children’s Choir director and even served on the Board of Trustees for two years. When not working at MDUUC, Marena teaches music and theater to children of all ages. Send email to


Mark Tuning

Music Director

Mark Tuning joined MDUUC as Music Director in September 2003. He holds degrees in Music Education and Choral Conducting from George Fox University (B.A.) and the University of Oregon (M. Mus.). In addition to serving for several years as Music Director for churches in Idaho, Oregon, Illinois and New Mexico, Mark also directed Jazz Choirs in several of those locations. Mark is also Music Director for Diablo Choral Artists, a community chorus based in Walnut Creek. He is a frequent soloist as tenor or countertenor and especially enjoys the creative opportunities of music ministry in a liberal congregation. Send email to

Brett Carson


Currently working toward his MA in Music Composition at Mills College in Oakland, Brett has performed and has had works performed around the country. Drawing from jazz, experimental, and concert music traditions, he seeks to incorporate an eclectic range of influences in his work. He currently performs and composes in two Oakland-based avant-garde groups, the Medium-Sized Band and Quattuor Elephantis.


Chuck Rosene

Church Business Administrator

Chuck Rosene is a 5th generation Unitarian, and comes to MDUUC after serving the Pacific Central District – UUA for 17 years as the District Administrator. He is a member of the First Unitarian Church of Oakland, where he sings in the choir and plays bass in the Joyful Noise band. Send email to

Tristan Thielman

Facilities Manager

I grew up in Walnut Creek CA, where my family and I joined the MDUUC community in the early 2000s. I also have over 4 years of custodial maintenance and landscaping experience with a little bit of a tech background thrown in the mix. I have worked a plethora of odd jobs over the years including sales, customer service, and working in the food industry. When I’m not at MDUUC I am usually out hiking in the shell ridge open space or composing music with friends. If you need to get a hold of me you can email me

Christian Melton

Publications Coordinator

Christian is currently a Diablo Valley College student studying Biology, Psychology, and Business working towards his transfer to a four-year institution. He joined the MDUUC staff in November of 2016 after working with his father as a Network Engineer Intern. He currently resides in Pleasant Hill where he spends most of his time reading, traveling, and working out. If you need to get a hold of Christian, please email him at