Despite being presented as a level 5 Swordsman, he would need more than 54 billion experience to even reach level 6.
His true stats are added to his preexisting stats, reading as follows:
Strength: 25
+1,364
Health: 21
+1,364
Recover: 15
+682
Defense: 16
+1,364
Vision: 6
+341
Dexterity: 8
+341
Speed: 9
+341
Han-Bin's level is unknown, but is most definitely high above 90, as he handles a boss-monster of level 80 in a single strike with no problem, and overpowers Alejandro (A level 91 with an incomplete blessing), and is even able to control his strength easily enough to hold him off without killing him.
It is highly possible that Han-Bin's true level is around 585. since the sum of his stats in lvl 2 is 80 (ch 2) and in lvl 4 is 100 (ch 3) we can see that he started with 70 stats and he gain 10 stas per lvl, the sum of his bonus stats is 5797 (missing 3 for some reason) wich divided by 10 is about 580 lvls plus his original 5 lvls he is lvl 585.
This is what i found in the fandom site of survival story of the sword king