Brogar's single strike can deplete your health quickly during the early
part of the game. Before fighting him, learn the Counterattack skill
from Craig (level 2 in sword). Place a bet with Craig, and challenge him
in the arena. During the fight, press [Counterattack] repeatedly. He
will have no chance of hurting you, and will keep losing health. When he
is down, you can take his weapon, money, potion, and a piece of the
golden sword (which is a part of the quest).