Brittany O’Diam (Horseman)

Brittany is a Certified Specialist in Estate Planning, Trust & Probate Law by the Ohio State Bar Association, and she is a dually Certified Specialist in Elder Law by the National Elder Law Foundation and the OSBA. Her practice focuses on estate planning, estate administration, elder law, asset protection, Medicaid, special needs planning and guardianships. She is passionate about helping her clients craft plans to address the unique aspects of each client’s circumstances. There is no one-size-fits-all plan here! Brittany is licensed to practice law in both Ohio and Florida (so she is officially a snow bird… in training). She currently serves as Chair of the Ohio State Bar Association Elder & Special Needs Law Section and is a current member and the Past-Chair of the Board of Trustees for the Disability Foundation. She is a member of WealthCounsel and ElderCounsel, and is active in the National Academy of Elder Law Attorneys (Past-President of the Ohio Chapter). In addition to keeping busy practicing law, she is also currently an adjunct professor at the University of Dayton School of Law.

In her personal life, Brittany is an active member of Be Hope Church in Beavercreek, Ohio, where she serves on various Hope Teams and on the Leadership Team. Brittany graduated cum laude from the University of Akron School of Law, after getting her BS in journalism from the E.W. Scripps School of Journalism at Ohio University, cum laude. She was a fifth generation graduate of Beavercreek High School and she is a second generation estate planning attorney. She is now happily settled in Beavercreek with her husband, Adam Horseman, and their two children, Camden and Jake. Brittany enjoys traveling, long walks (beach optional), and reading.

Kim Cullman Estess

Kim is a Certified Specialist in Estate Planning, Trust & Probate Law by the Ohio State Bar Association, and she is a dually Certified Specialist in Elder Law by the National Elder Law Foundation and the OSBA. Kim’s practice focuses on estate planning, estate administration, elder law, asset protection, Medicaid, special needs planning and guardianships. She believes providing outstanding service requires more than just excellent legal work—it also involves taking the time to establish a strong relationship with each client in order to truly understand their unique goals. Kim currently serves as Chair of the Board of Directors for United Rehabilitation Services, as Secretary for the Ohio Chapter of the National Academy of Elder Law Attorneys, as a member of the Advisory Council for St. Leonard, and as a member of the Planned Giving Advisory Committee for the Kettering Health Foundation. Kim was recently selected as an Ohio Super Lawyer for 2026 and by the Dayton Business Journal as a 2025 Women Who Mean Business honoree. She is a proud member of the Leadership Dayton Class of 2022 and was a Dayton Business Journal Forty Under 40 Award Recipient in 2022. She is also a member of the Ohio State Bar Association, the Dayton Bar Association, WealthCounsel and ElderCounsel. 

Kim graduated from the University of Dayton School of Law, where she was a member of the moot court team and the law review, and where she currently serves as an adjunct professor. She earned her BA in Journalism from Indiana University. Kim was born and raised in Centerville, where she now lives with her husband, Adam, and their daughters, Cece and Abby. In a weird twist of a fate, Kim and her family currently live in the home where Kim herself grew up! In her spare time, Kim enjoys running, playing golf, and enjoying great food.

Madison Batley, Associate Attorney

Maddy Batley joined the firm as an Associate Attorney in 2022. Her practice focuses on estate planning and estate administration, elder law, Medicaid and asset protection, special needs planning, and guardianships. She serves as the Secretary for the Centerville Washington Township Foundation and is a member of WealthCounsel and ElderCounsel, as well as the Ohio State Bar Association and the Dayton Bar Association.

Maddy was born and raised in Peterborough, Ontario, Canada. She earned a lacrosse scholarship at Tiffin University, where she graduated magna cum laude with a degree in Criminal Justice. Maddy received her law degree from the University of Dayton School of Law, where she was a Dean’s Scholarship Award recipient. Maddy currently lives in Middletown, Ohio, with her husband, John, and their dog, Ollie. When she’s not working, she enjoys reading, camping, and spending time with her family. 

Marissa Tregoning, Associate Attorney

Marissa Tregoning joined the firm as an Associate Attorney in 2026.  Her practice focuses on estate planning and estate administration, elder law, Medicaid and asset protection, special needs planning, and guardianships.  Marissa loves working with people and getting to know clients, and she takes pride in helping them feel legally prepared to face whatever comes their way in life.

Although she is new to OELG, Marissa brings a wealth of legal and other professional skills with her to her new role.  She graduated from The George Washington University in Washington DC, where she recevied a bachelor’s degree in both Human Services and Public Policy focused on Political Science.  Marissa then began her professional career in social work at the Clark County Board of Developmental Disabilities.  After a few years in that field, Marissa attended law school at the University of Dayton School of Law, where she earned her juris doctorate in 2012.  Following law school, Marissa spent almost 14 years working in Acquisition as a Contracting Officer for the Air Force and the American Battle Monuments Commission.

Marissa lives in Englewood with her husband, Brian, their two kids, Caroline and Will, and their French Bulldog, Eliza.  She grew up in Springfield and graduated from Shawnee High School.  When she is not working, you will find her at Vandalia-Butler school events (Go Aviators!) and carting her kids to and from sports and music activities. Marissa also loves traveling, going to Indian Lake on summer weekends, and attending Christ Episcopal Church with her family, where she teaches the Sunday School class each week.