Interminable

Both Thai BL dramas feature BillyBabe as the main leads and have strong Thai supernatural themes and folklore. The Sign is an action series with them acting as detectives while Interminable is a historical drama.

They are both historical Thai BL dramas about fated lovers set around the same time period (1910s~1920s). Both have an upper class character together with a lower class character and struggle with societal acceptance of a male-male relationship during that time.

Both are fated lovers that ended tragically in their past lives and are restarting their love again in this current lifetime after their past memories are revived.

"Interminable" and "I Feel You Linger in the Air" are historical drama series center around an estate that is significant to the protagonist transmigrated either from the past or the future. Either way, the protagonist has an infinity with the owner of that estate, a promise awaited to be fulfilled.

-Thai Bl
-Reincarnation
-Both have historical plots/aspects
-Female lead trying to get between the two

Overall, the two dramas have similar vibes/atmosphere as well as plots.

-Thai Bls
-Historically centered plots

Both are historical Thai BL dramas with a past and present timeline that features a love story between a human and a ghost that is trapped inside an old house.