MC is involved in an accident which leaves him disabled for life. The game company offers to help by puuting him in the game. He forgets to logout at the end of beta and lives in the still game world for some time until the game goes online.
He gets lucky enough to know the locations of all the training centers in the beta phase which he immediately starts finishing after the game begins. He has two younger siblings a brother and a sister. He is insanely OP with less level but extremely high stats since he finishes master level training center. He has some class related elemental swordsman.

Now if anyone actually remembers the name pls help out.

http://royalroadl.com/fiction/638

your looking 4 Life in New World (LNW) by olyver if it has him going to training halls all the time. depends on own stats not ones gain from lvl up. destroys guild singlehandly and was on his way to city with giant problem. hiatus far as I know