A person celebrating an anniversary is often referred to as an "anniversary celebrant" or simply the "celebrant." In the context of a couple, they may be called "anniversary partners" or "spouses." The term can vary based on the nature of the anniversary being celebrated, such as a wedding anniversary or a milestone event.
A Loner.
100 anniversary.
.
a poor person maybe......
quasquicentenial
Octocentennial or octocentenary.
centenary
bicentennial
ghosts birthday
A classic name for a birthday person is "Birthday Boy" , or "Birthday Girl".
silver anniversary
it is an anniversary