Comrade

Comrade is the name given to someone who belongs to the same social group, party or company. It literally means "friend", "colleague", but it also means "ally". The term can refer to someone who has the same beliefs or values. That way, in Communism, people who belong to the Communist Party address each other as "comrade". 
Terms like this avoid using titles, rank or any other sign that one person is better than, or different from, another.