The use of inhabited Virtual Environments is continuously growing. People can embody a human-like avatar to participate inside these Virtual Environments or they can have personalized character acting as mediator; sometimes they can even customize it to some extent. Those Virtual Characters belong to the software owner, but they could be potentially shared, exchanged and individualized between participants, such as already proposed by Sony with Station Exchange. Technology with standards could significantly improve the exchange, the reuse and the creation of such Virtual Characters. However an optimal reuse is only possible if the main components of the characters: geometry, morphology, animation and behavior, are annotated with semantics. This may allow to users searching for specific models and customize them. Moreover search technology based on the Web Ontology Language (OWL) can be implemented to provide this type of service. In this paper we present the considerations to build an ontology that fulfills the mentioned proposes.