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Karl Arian A. Castillo

Senior Partner

  • kaacastillo@fnslaw.com.ph

Karl joined FNS in 2002. He was promoted to Senior Associate in 2004 and admitted to the Partnership in 2008. He has been in litigation since his early years with the Firm but he also involves himself in energy law, arbitration, and environmental cases. Assiduous preparation and trying to predict all possible ramifications of my decisions help me become a better lawyer because fear and stress are both rooted in the unknown.’  He states, ‘striving for perfection even if it seems unreachable makes one a better person, which ultimately redounds to the benefit and success of FNS.’

Karl considers having a wonderful and loving family as his greatest blessing. ‘My family is the center of my universe and the fountain of my happiness. Joyce, Kim, Gab, and Edj are my raison d’ etre.’

Karl Chairs the Litigation and Dispute Resolution group and covers the Energy Law practice group of the Firm and can be reached at kaacastillo@fnslaw.com.ph

KARL ARIAN A. CASTILLO

KARL ARIAN A. CASTILLO (Senior Partner), born in 1975, admitted to the bar in 2002, Philippines.  B.A. in Political Science (University of the Philippines, Manila); J.D. (Ateneo de Manila University).

Arbitrator: Wholesale Electricity Spot Market (WESM)

Director: Integrated Bar of the Philippines Makati Chapter 2023 to 2025

Auditor: Integrated Bar of the Philippines Makati Chapter 2025 to 2027

Director- Supreme Court Unified Legal Aid Service

Member- Supreme Court High Performance Courts Committee

Practice Areas

  • Arbitration
  • Energy
  • Environment
  • Litigation & Dispute Resolution
  • Projects, Mining & Natural Resources

About Us

FNS has been providing top quality legal service in the Philippines for more than thirty years.  We maintain a visible presence in the Makati Central Business District with our headquarters in the main hub of business in Ayala Avenue and a liaison office in Hong Kong.

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Our Expertise

  • Arbitration
  • Corporate & Commercial Practice and Corporate Rehabilitation
  • Energy
  • Environment
  • Family & Estates
  • Immigration
  • Intellectual Property
  • Labor
  • Litigation & Dispute Resolution
  • Projects, Mining & Natural Resources
  • Real Estate & Franchising
  • Taxation & Appeals

CONTACT US

23rd Floor, Multinational Bancorporation Centre, 6805 Ayala Avenue, Makati City 1226 Philippines

  • info@fnslaw.com.ph
  • (632) 8812-8670
    (connecting all departments)
  • (632) 8813-6063
  • (632) 8818-4542

About Us

FNS has been providing top quality legal service in the Philippines for the last twenty five years.  We maintain a visible presence in the Makati Central Business District with our headquarters in the main hub of business in Ayala Avenue and a liaison office in Hong Kong.

Facebook Twitter Linkedin

CONTACT US

23rd Floor, Multinational Bancorporation Centre, 6805 Ayala Avenue, Makati City 1226 Philippines

  • info@fnslaw.com.ph
  • (632) 8812-8670
    (connecting all departments)
  • (632) 8812-7199
  • (632) 8812-4251

Our Expertise

  • Arbitration
  • Corporate & Commercial Practice and Corporate Rehabilitation
  • Energy
  • Environment
  • Family & Estates
  • Immigration
  • Intellectual Property
  • Labor
  • Litigation & Dispute Resolution
  • Medical Malpractice Actions
  • Projects, Mining & Natural Resources
  • Real Estate & Franchising
  • Taxation & Appeals
  • © Copyright 2026 Fortun Narvasa and Salazar Law. All rights reserved.
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