Investigation and mystery
the leads in both are trying to uncover the secrets of the kingdom
both are historical detective dramas

Both have strong male lead
Both wuxia dramas with wuxia fights
both has good romantic stories
Both have strong female lead

Both drama are badass Wuxia drama to the core story
both have strong male lead and strong female lead
both have amazing Wuxia fights
both are great watch

Both dramas are about fire fighters
but I hope Blue flame is better than flaming heart
because the romance destroyed that other one

Both Military drama but one in rebublican era and the other one is in present times
Both have good comradery and both have unique friendships fighting the enemy

Both dramas have brotherhood and comradery
both dramas fighting the Japanese occupation
Both have strong male leads and conflicts also both have traitor
one is war the other espionage

Both drama are republican era drama ,, both fighting Japanese occupation of china
Both have strong male lead who endure so much loss
both have good bromance and a traitor

Both have the concept of the grim reaper
Both have suicidal souls turn into reapers
Both have individual cases of people to save from death

Both drama are about a Psychological criminal cases
Both dramas have a detective with close relationship to the suspect
Both dramas have trauma from childhood

Both drama are about psycho killer and detective solving his cases
Both drama have psychological trauma and brutal cases

Both drama deals with a kidnapped daughter and both leads try their best to find their daughter and fight for her life

Both dramas are detective dramas
Both dramas have older detective and younger partner solving criminal cases