Well, I don't see any point in not letting the members to use specialist tags or whatever they are called.
If they want to use, then go on, but imho it doesn't look so nice, as Hopea just said.
Also, some people put an organization's name to that place when they are in one, like OLDA[Clan]ExDawg
There is an organization for people who like TK. Its name is Taekkyon League, and in short it's TkL.
But yeah, if you really feel like it, feel free to put a specialist tag before the Blood tag.
Also, I don't
hate them, I just think it doesn't look so nice, but it's still acceptable.