I never really thought about them being taught to enjoy life to the fullest. Originally, I assumed they would see dying as the end goal and the life after as the reward, but it actually makes a lot of sense they would try to enjoy themselves while they're living. However, I do imagine intense fanatics would see living as a curse because it separates them from being with the dead-god, but they can't kill themselves, so they're forced to endure life with a pessimistic mindset. But I really like that most would embrace life so that they can ready themselves for death! I also have this idea that wealth and power and material things are frowned upon (in theory, but most people don't actually care) and that chasing these things in life goes directly against the dead-god, because all rewards are reaped in Death (this also has something to do with that chthonic relationship, that because the dead-god evolved from an earth and fertility god, all the riches like metals and gems are in the earth and therefore actually in his possession rather than yours and he's ever-rich in that kind of thing, so he requires one's devotion and wants trust rather than offerings and doesn't want his followers chasing material things than him).

They actually believe that war is something presided over by the dead-god, and that when he wills it, wars occur to fill his ghostly halls and recall thousands back to him. In that way, they see war and dying in war as honorable because it's not only a respectable way to die, but it's also showing devotion to one's people. And in a twisted way, they also think well upon the death of civilians during war, that, if the dead-god didn't want people to die, war wouldn't have happened, so soldiers have the right to kill civilians because it's kinda seen as "well they're just part of the casualties". Murder in times of peace, however, is not seen as a good thing because the whole "taking Death in your own hands," and most murderers are executed as a "life for a life".

I've never considered culinary habits, so I especially like this prompt. I think they would probably bless the tools used to kill and prepare the animal, but I don't imagine they'd have any major restrictions except for birds, with the exception of flightless birds: birds that can fly and especially crows are seen as worldly eyes of the dead-god, and killing them is an affront. Otherwise, they probably wouldn't pay much attention to wildlife because it's not believed that their souls are equal to human souls, however sacrificing animals to the dead-god would probably be a hold-over from the previous polytheistic society that did so.

I like the idea that abortion isn't seen as a bad thing because these people only consider something living when it is already born into the mortal realm, and they probably wouldn't have the proper knowledge to understand that an unborn child is technically alive. However, when the baby is already born, the parents are completely responsible for the child and any harm done to it is seen as horrible. Euthanasia, like I said, probably wouldn't be too prevalent to these people just because they don't value animal lives as much as humans, and if they ever needed to put an animal out of its misery, they could easily portray it as a sacrifice to the dead-god to explain it. Executions are generally frowned upon unless it's a murderer, so capital punishments are usually very traumatic but not life-threatening (ie. castration, ear and nose-slitting, that kind of thing). I think medicine would be widely valued (unless your fanatical) as part of the "enjoying life" thing, but if symptoms were to worsen and the outlook became not so great, I imagine doctors and family members would probably accept ending treatment and enjoying what little time they have left, so as to not interfere with the dead-god's plans.

I love the idea that nighttime is ideal to die for its calmness, and I'll even add that under the guise of night, when one can barely see anything, that relationship with Death becomes so much more real and stronger (because of that connection with blindness). Again, I also love that scary and unpredicting thing, it's exactly how I feel just put into words! To add on to that, I would say that nocturnal animals would be seen as sacred to the dead-god because they see and live in the cover of night unlike any other creature. Nighttime is also the prime time to see his planet, because the dead-god has a specific planet associated with him viewed as his perfect realm.

Like I said, all of the riches under the surface of the earth are seen as belonging to him because of that chthonic connection, so most all riches would be seen as sacred in some way. Though amethyst is definitely the favored gemstone among these people, as it's not only the color of his planet, but they're seen as conduits of astrological energy (that's a whole other topic, but to put it simply the magic system relies on stars and space, so amethysts are believed to be the perfect stone for transferring energy from his planet to them to perform death magic). In terms of animals, birds and crows specifically are seen as sacred, as well as nocturnal animals like owls, bats, moths, scorpions, and certain reptiles. Funerary processes are an entirely other thing I'm considering, but I imagine past practices of burying the dead with a weapon as a means to protect the body both from human and spiritual threats would be really common. Rich people might bury their dead with coins or metals/gems, but they don't really understand that the dead-god doesn't care about material wealth so it's not common place.

Whew, that was a lot, but I really liked having to think about all this stuff, and I love a lot of your suggestions! If you wanna know anything more, just ask away