Meet our team

Mariia Matsepa and Oscar Butragueno founded Koroliuk Consulting. Oscar has 25 years of experience world's most remote areas in the design, implementation and monitoring, and evaluation of humanitarian programs. Mariia has 20 years of experience in Monitoring, Evaluation, and Learning (MEAL) activities and fundraising in Eastern Africa, Europe, and the Middle East. 

Oscar Butragueno

Oscar is a seasoned humanitarian and development professional with 25 years of experience coordinating large-scale emergency response and recovery programs across seven global regions, including Europe, the Middle East, North and Latin America, the Caribbean, South Asia, and West and East Africa. He holds a Master's degree in Social Policy and Planning from the London School of Economics (LSE) and a Master's degree in Political Science and Administration from Complutense University, complemented by studies at the Universities of Bristol (UK) and The Hague (Netherlands).

A specialist in disaster preparedness, emergency response, and recovery, Oscar's expertise spans human rights, social protection, migration, public health, and water, sanitation, and hygiene (WASH). He is an innovator, having developed and implemented a humanitarian action performance system and automated emergency response and preparedness plans.

As an empathetic and skilled leader, Oscar excels at building and managing teams in challenging environments. He is adept at talent identification, recruitment, and staff development, and possesses a proven ability to analyze complex, multi-sectoral issues, develop actionable plans and protocols, and communicate effectively.

His communication skills extend to media engagement. During the pandemic, he founded Thirst4Thrill, a company dedicated to promoting socially relevant films.

Beyond his professional work, Oscar is a nationally licensed (C License) US Soccer coach, inspiring youth teams to develop essential life skills, build confidence, and achieve their full potential, both on and off the field. His coaching has also led to several league titles and fostered a strong sense of team pride. He is also a US Soccer licensed referee and continues to explore innovative soccer performance methods, including "coachoskar.com"


Olena Domanchuck

Olena is a highly effective legal expert specializing in cases of domestic and gender-based violence, with a proven track record of success from local courts in Ukraine to the European Court of Human Rights. She is a co-author of the "Assessment of the National Perpetrators’ Response Mechanism in Ukraine" (2021), commissioned by UNFPA through Koroliuk LLC for the "EU 4 Gender Equality: Together against gender stereotypes and gender-based violence" program, a joint initiative of UN Women and UNFPA funded by the European Union.

Olena possesses in-depth knowledge of the legal process, demonstrated by her successful representation of a domestic violence survivor. She provided comprehensive support, including meticulous documentation, accompaniment through the Kyiv regional, appellate, and supreme courts, and ultimately secured a favorable judgment at the European Court of Human Rights.

Her expertise encompasses all aspects of legal representation for survivors of domestic and gender-based violence. This includes preparing documentation for court, representing clients during police interviews and court proceedings, providing legal counsel that facilitates successful settlements, and offering essential psychosocial support and referrals to relevant social services, such as the Department for Social Services and the Department for Child Services.

Since 2016, Olena has maintained an impressive 90% success rate in nearly 100 cases, underscoring her dedication to achieving justice and empowering her clients.



Mariia Matsepa

Mariia is a highly skilled Monitoring & Evaluation (M&E) expert, possessing extensive experience both as an in-house specialist within UN agencies and as an external evaluator for humanitarian and development projects. She holds a Master of Arts degree from the College of Europe and a degree in Political Science from the National University of Kyiv-Mohyla Academy.

Beyond her professional life, Mariia is a talented aspiring singer with a passion for art. While currently engaged in numerous professional and personal pursuits, she continues to be a valued volunteer advisor and a source of inspiration.

And our other top contributors, which we will include in due time!