Leicester "will be back" after their relegation from the Premier League, says Aiyawatt Srivaddhanaprabha, who revealed he has had "offensive" messages asking him to sell the club.
His family have owned the Foxes since 2010, with Aiyawatt taking charge in 2018 after the death of father Vichai.
In that time, they have been promoted, won the Premier League and FA Cup.
"Relegation is undeniably a significant setback, but it will not define us," the chairman said in a statement.
The Foxes' relegation back to the Championship, under boss Dean Smith, was confirmed on the final day of the season despite a 2-1 win over West Ham.
"Today we share the loss and the pain of relegation together," Srivaddhanaprabha continued. "But we will be back.
"We achieved things and share experiences together that nobody will ever forget. We completed an ascent nobody thought was possible - from relegation favourites to Premier League champions and one of the greatest sporting stories ever told."
Several of Leicester's key players, including Youri Tielemans, Jonny Evans and Caglar Soyuncu - plus manager Smith, who replaced the sacked Brendan Rodgers with eight games left - are out of contract, meaning major changes are likely this summer.
Srivaddhanaprabha continued: "These milestones [winning the Premier League and FA Cup and having European runs] place our situation today into quite stark context, but I reference them to highlight the progress we have made as a club in the last 13 years, which gives me confidence that we will build again.
"This past season has been the most difficult for all of us to endure. Relegation is a consequence of 38 games and over that period, we haven't been good enough.
"Over the coming days and weeks, we need to reflect on the processes and decisions that have brought us to this point. What we learn from this experience must convert into action that makes us stronger and prevents this happening to us again in the future.
"This responsibility that I continue to live is one of the greatest responsibilities in my life and I will continue to put everything into it.
"I have received a massive number of messages from our fans - both positive and negative. Some want me to sell the club, some using offensive and thoughtless words, and some have been outright abusive.
"But for every hurtful message I have received, I have also received messages of support, of appreciation, of unity - both remotely and from people I have met anonymously in public, who always come to say hello to me and to my family. It means a lot to us."