Bromance/soulmates, in both series there are two MLs, who care and support each other, while also stimulating each other's growth and aspire each other, both cover long period, 1 year in RLASS and 10+ in Hikaru, MLs personal growth - physical and psychological.

Similar vibes, in both series there are two MLs, who care and support each other, while also stimulating each others growth, both cover long recovery period, MLs personal growth - physical and psychological.

Both dramas are bls about reincarnation in parallel world, in vice versa it is about different bodies, two worlds - the same bodies.

Both dramas share the part, when one ML has a child (daughter in History, sister in the second); the second lead starts caring about ML and a child. Both sweet!

Both dramas show unexpected intergenerational friendships, which change the life for both sides. In Navillera - an old man and a ballet dancer, in Ossan.. - middle aged manager and his son's friend - young gay and medical student. In both cases, MLs influence each other in a good way.

Both dramas have BL elements, however they are more like background, whereas the main plot is more based on family problems, personal growths and acceptance. Fathers in both dramas try to adjust, accept their children as they are and want children to be happy.