Memory in the Letter

Time travel. In the finale the age difference between the main characters is more than 20 years. The main character loves his friend's son.

-Thai Bl
-Parallel universes
-Traveling
-Love triangles

-Thai Bls
-Parallel universes
-Traveling
-Heartbreak

Both are supernatural/fantasy Thai BLs in which the one ML sees someone in mirrors. In MITM he's afraid of that stranger whereas in MITL he falls in love with him.

Another story of mirrors and soulmates. This one is really bad but there is the same magic mirror trope so....

Vice Versa is about parallel universe and it is a bl romance. There are promises given to meet again...

Even if this series is about parallel universes where he has traveled to a different time to this universe, even though Absolute Zero is a straight time travel story the vibes between Absolute Zero and Memory in the Letter in almost the same.

Both are Thai BLs about parallel worlds, with one ML crossing over to the other's world.
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Both of these are BL fantasy romances involving the two male protagonists seeing each other through a mirror.

In both of these gay fantasy romances, a connection forms between 2 men living different lives, impossibly connected by the writings of one/both.