[quote=@Slime]
Just how powerful does a character have to be to beat a Realta? I can see that a single one can give a lot of trouble so I was wondering that.
[/quote]

From what I gather, the general consensus is that one needs to be a rather strong/lucky/smart hero to beat one (only one, if you get ganged up on, then your chances of survival are nearly zero). Anything less and they get destroyed. There was an instance where 3 or 4 heroes ganged up on a single Realta and three of them nearly died.