Made
by makers.

Costas Mantziaris

Co-Founder & Managing Partner

Costas co-founded REBORRN in 2018 to help brands make better decisions through sharper strategy and customer-centric experiences. With 20+ years in leadership roles, Costas has led CX, strategy, and transformation work for global CPG and FMCG leaders such as The Coca-Cola Company, Philip Morris International, and Bayer. By merging data with intuition, Costas helps enterprise clients build better experiences.

Giorgos Vareloglou

Co-Founder & Managing Partner

Giorgos co-founded REBORRN in 2018 with a thesis that marketing is moving faster than marketers can. With nearly two decades building and scaling businesses, he now partners with global marketing leaders to turn strategy into tangible outcomes. His work spans operating model design, change acceleration, and in-market activation for brands including The Coca-Cola Company, Philip Morris International, L’Oréal, and Bayer. A regular speaker at industry conferences, Giorgos writes about change, people, and how modern marketing organisations should be built.

Kelly Panagiotidou

Managing Partner

Kelly is Managing Partner at REBORRN, leading the firm’s operations and organisational design. With 20+ years in leadership roles across hospitality, financial services, and high-growth tech, including ING Group, Starwood Hotels & Resorts, and Tripsta, she specialises in building the operating models, culture, and ways of working that enable performance at scale. At REBORRN, Kelly ensures every engagement runs smoothly, from internal team alignment to client delivery.

Dafni Prosalika

Partner

Dafni helps Fortune 500 companies rethink how they operate, from customer experience and marketing to commercial models for the digital age. Before REBORRN, she led Marketing and Growth for a leading B2B FMCG company in Southeast Europe and headed Commercial at Greece’s largest digital agency. She hosts Marketing Factories, a vidcast in partnership with Effie Europe that goes behind the scenes of the most effective marketing teams. A psychologist by education, Dafni is endlessly curious about what drives people’s choices.

Mathilda Nathan

Partner & Co-Founder & CEO, BORRN

Mathilda is Partner at REBORRN and Co-founder and CEO of BORRN, REBORRN’s zero-to-one venture arm. With 10+ years in leadership roles across the European start-up ecosystem, including Director of Sales Strategy at Deliveroo (12 markets), CRO at Side, and VP of Growth at Zego, she brings deep scaling expertise to enterprise clients building new products and capabilities. A certified Business Coach (INSEAD), Mathilda combines growth strategy with a people-centred approach to leadership.

Mike Polizos

Practice Lead, Product & Design

Mike leads REBORRN’s experience design practice, a multidisciplinary team of UX designers, storytellers, illustrators, animators, and engineers. He joined as employee #2 in 2018, pivoting from a creative career into consulting, and has since built one of the most awarded design teams in the region, including multiple Red Dot Design Awards. Mike brings innovation to how creative work gets done, helping enterprise clients turn complex challenges into tangible, beautifully crafted experiences.

Antonis Ventouris

Practice Lead, CX & Process Innovation

Antonis leads CX and process innovation at REBORRN, helping teams turn customer, data, and operations complexity into simpler journeys and better performance. With deep expertise across performance marketing, analytics, CRM, and business process optimisation built at Mindworks and iProspect (Dentsu) for brands including Allianz, Mondelez, Eurobank, and The Coca-Cola Company, he designs smarter operating processes that improve experiences end to end.

Dimitar Andonov

Principal Consultant

Dimi is a Principal Consultant at REBORRN with 20+ years in marketing, portfolio growth, and innovation across some of the world’s most iconic global CPG brands. His approach fuses empathy, creativity, and technology to transform products and services into meaningful human experiences. At REBORRN, Dimi helps enterprise clients unlock growth through sharper consumer insight and smarter go-to-market strategies.

Vesna Vlahovic Dasic

Principal Consultant

Vesna joined REBORRN in 2025 as a Principal Consultant, bringing 20+ years across marketing, consulting, and commercial leadership in Central & Eastern Europe. She spent 15+ years at The Coca-Cola Company, leading marketing and commercial teams across Austria, Adria, and Bulgaria and delivering award-winning work that balanced creative excellence with measurable impact. Vesna’s approach is grounded in empathy and co-creation. She is currently completing a PhD in Neuromarketing, focused on how technology and human behaviour shape modern brand growth.