You can have as many as possible accounts as you want, what are not allowed  is to be using one account for the advantage of another, or joining the same campaign with two or more accounts. If you do not go against such rules, there is nothing bad to have as many as possible accounts as you want. Even, if you have two accounts and you do not join the same campaign and not meriting your same accounts, there is no offense at all, anyone irrespective of the ranking can have two or more accounts.