Same for me, didn‘t know the company and the website says absolutely nothing about what they do. Wikipedia helped me; it‘s an AI chat bot service where you can interact with customizable characters.
Check their Reddit. Their userbase is rabid and has a casual relationship with reality. I checked a few random posts and there were people talking about how their life was over or how character.ai was the only thing that worked for therapy.
Honestly I’d be glad if this type of product disappeared, it’s just predatory on people primed for ai psychosis