Maybe they’re nice. Maybe they’re a bit unknown to you. Maybe they have a special interest in your research area.
Your examiners might be experts. They could be among the many people you’ve cited in your thesis. Maybe they know your supervisors; they’re friends, more than professional colleagues.
There are lots of possibilities for examiners – and lots of certainties too.
They will have prepared. They will be ready. They will have questions. They will have expectations for you, the viva and themselves.
They will not have been randomly selected – supervisor friends or not, experts or otherwise – they will have been asked for a reason. They will have been selected as a good choice.
Best choice? Perhaps. Capable? Certainly.
Find out who they are and you can help yourself as you prepare for your viva.