Once the GDPR comes into place next month (25 May 2018), you can apply to have your personal information removed from your account, yet right now we don't currently do this.
To clarify further, here's a tiny snippet regarding the situation post-GDPR legislation coming in:
During your time here on the forum, any personally-identifiable information (PII) is processed/stored by us for provision of forum service on the basis of (a) consent and (b) legitimate interest, as defined by GDPR.
If your actions result in your forum account becoming banned, we will anonymise any personally-identifiable information where possible, but keep your post-trail (to maintain readability of forum threads) and the minimum of other data that is necessary to enable any forum-ban to be actioned. In most cases this could be any or all of: the email address you signed up with, the IP address(es) used to access forum services, your forum-username, and (if you are game-banned also) your SteamID and Battleye GUID.
After a ban, whether consent is maintained or not, we retain the right to process these specific items of data as above, purely to facilitate forum-exclusion and protect our other community members, under 'legitimate interest' basis clause.
Departing forum-users (post-GDPR)
without bans, who wish to have their accounts anonymised, will be able to request this, at no cost, and such data will be anonymised in due course. Once again, forum posts will be kept, but rendered anonymous, so that conversations still make sense. All other data will be obscured so that it is no longer personally-identifiable, or removed completely where not needed for exclusions or bans. Again, the basis for any retained data is 'legitimate interest' under GDPR.
We will be undergoing a process nearer the time, when our privacy policy will be updated and publicised, and our rights to process and hold data will be refreshed. At that time, forum-users will be required to signal their continued explicit consent (or not), in order to remain a member of the forum, in accordance with the new law. Anyone lapsing, not giving consent or failing to respond within a period of time (to be specified later) will have their accounts anonymised automatically and all PII deleted; anyone within that subgroup who is also banned on game-servers, Teamspeak or forum, will have sufficient data retained to facilitate those bans whilst RPUK is in operation, and any remaining non-vital data will be anonymised, exactly as explained above, in accordance with the 'legitimate interest' basis of the law.
I hope this answers your questions fully.