I'm trying to ban from my chan those who use a certain Name on their script

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»»»» /whois list for: «nick»
»»»» address: blahblah@yournetwork
»»»» name: Lord
»»»» services: registered
»»»» channels: ...
»»»» server: ...
»»»» end of /whois list for: «nick»

So, in this case, imagine I wanted to auto ban everyone using the name "Lord" in the real name field. How do I do that remote?
It would be something like

On *:JOIN:#ChannelName: {
if (realname == name) {
ban -k etc....
}

Any suggestions?

If the network you're on uses Unreal as IRCd (/version) you can ban people pre-emptively by realname with +b ~r:realname_here (see unreal ban types).
You cannot actively check someone's realname upon them joining the channel unless you /whois every person on-join.

The extend ban of unreal is a module, so IRCd can be unreal and ban like ~r|c|q can't be used.

Mirc's internal address list (ial) is not storing realnames, nor gives the on join event that information.

You'd have to whois everyone joining, check the rawlines of your whois reply, and compare the right one it to a list of blacklisted realnames.

e.g. (on unreal, the raw line 311 (whois reply) contains the realname as 6th space-delimited token onwards)

Note, this line of whois reply does not deliver the channelname in itself.
On unreal ircd, you could set bans directly on realnames, check http://www.vulnscan.org/UnrealIRCd/unreal32docs.html#feature_bantypes

Yes, but isn't there any command that retrieves the realname?

If i want to set a variable with the realname of the last user that joined the chan, how would i do it?

instead of whoising the nickname, you may just make a /who nickname

this command will return in the raw 352 the realname.

here's an example:

23:44:13 -> irc.voila.fr WHO nickname
23:44:13 <- :irc.voila.fr 352 TropNul * theident thehost hisnetwork nickname H :0 THEREALNAME
23:44:13 <- :irc.voila.fr 315 TropNul nickname :End of /WHO list.

THAT really helped!!! RESOLVED! thanks a lottttttttttttttt