So, after noticing the whole "you can go back 4 minutes before a persons's death" having roots in the japanese superstition about the number Four, which is pronounced the same way as "death" (shi), I was wondering about other similar references on japanese culture you guys have noticed. Anyone?

I believe red has the symbolism for healing, demon repelling, or sickness repelling. So red being Sissel's main color could represent his presence in the world of the living as a dead person.

The Red-Equals-Sickness symbolism quickly gave way to a new dualism between evil and good, between death and life, between hell and heaven, with red embodying both life-creating and life-sustaining powers.

Source

Having just finished it myself, I noticed temsik, is actually kismet (meaning fate or destiny) backwards, I wonder was this in the original Japaneese translation?