My take on it is that gods are just beings, albeit on a far higher power scale. They quarrel, have feelings and try to outwit and possibly destroy each other. As I understood "The History of Magic", the Ways are relics of the creation of the glyphs. Some glyphs go well with each other, some don't. So to make magic more controlled and safer for everyone involved, glyphs and ways go hand in hand.
I also think gods have flaws, and probably, some day, Talad will come to think "Hey crap, I totally should have made glyphs so that only my followers can use them.". But gods, being attention whores, would also like the attention "Wow, you're the dude who made the glyphs, fancy.".
As for gods and magic there seems to be a clear link between the two. If you are a true follower of a god, that god would help you understand his areas of knowledge better and hence improve your ability to use magic in that respect. If you follow Dakkru you understand the nature of death and hence would be able to cast better Dark Way spells.
As to the Death Realm, I would surmise there are things that even predate the gods. Since all races, irrespective of being created in Yliakum or not, are going to the Death Realm, this might be a place that has nothing to do with the creation of life in Yliakum. And perhaps Dakkru one day decided it would be a nice place to hang out, he seized power and claimed the DR his own and since that day, he's in charge. Since there are things even the gods can't change, perhaps the DR is one of those and Dakkru just has to accept that whatever dies heads his way. Now, that makes Dakkru a hell of a deity since he gets to decide who exists and who not, and as seen with the BF followers, uses that privilege too. Perhaps the gods have a truce among themselves and Dakkru just can't afford killing believers of the true gods or else draw their ire?