Two kinds of epithet
An epithet is a short descriptive name added to a character's name or used in its place. In murim stories the nickname tells you the weapon, school or reputation before the fighter speaks. Murim mode shows each one in English, Hangul and hanja, for example Blood Flower 혈화 血花.
Fantasy mode builds titles from patterns. The pattern the plus an adjective plus a noun gives the Pale Sovereign. A noun plus -Bane gives Light-Bane. Bringer of plus a noun gives Bringer of Ash. Some random words may need a small edit, so read the result aloud.
Find one by weapon, side or role
The murim finder mixes filters. Side: righteous, unorthodox or demonic. Weapon: sword, blade, fist, palm, spear, fan, whip or staff. Role: assassin, healer, scholar, monk, beggar or musician. You can also pick female, young or elder. A righteous young swordswoman may get Cold Snow Flower 한설화 寒雪花. An unorthodox assassin may get Black Wind or Ghost Mask.
Overused names and fresher swaps
Some nicknames fill so many stories that readers roll their eyes. Heavenly Demon, Sword Demon, Blood Demon, Poison Demon and Mad Demon all carry the Overused tag. Details lists fresher swaps. For Sword Demon, try Ghost Blade 귀도 or Shadow Sword 암검. The flags come from reader complaints, not from a count. See also overused names.
Read Check meaning. Sound Demon sounds like a lewd phrase in Korean. Several staff nicknames contain "bong", which is English slang for a smoking pipe.