I haven't found any reliable sources, but I believe Raikou, Entei, and Suicune all come back after the Elite Four if you didn't already catch them.
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yes it will come back if you defeat the E4 and Lance. It will keep being that until you catch them. Same rules apply to other legendarys
you have to beat the elite four first then you can come back and he will be gone
In Gold, Silver, Crystal, Fire Red, and Leaf Green, no. If you KO them, you'll never find them again on that game file. In any games starting from Generation IV, however, you can KO them as many times as you want, and they'll always come back…after you beat the Elite Four and Champion again, that is.
If you mean the guy blocking a route to the right,then don't bother.You come back there AFTER the Elite Four.Go right past him straight,then left.There should be the exit.
One.