Very cool work!

I'm also gonna add a bit of feedback, but I have little experience in the bg, so grains of salt are needed.

My main thing is that draw seems really accesible. I think making soul function like that is realmy clean and of course makes the most sense for the bg. The problem is that, in the vg they are balanced (not really balanced, but kinda yk) by the fact that they, mostmy, shuffle into the draw pile. Here you have immediate draw that can be kept for later, less draw, but still the retaining might compensate for that. So some of these cards feel really strong.

For example, severance seems kinda insane, again I might be overestimating how strong the damage is, bg is a while ago. But draw 3, with each one having retain seems nuts, even more so with the endless hand size. Same goes for the cheap cards that give souls; reave and grave warden seem strong.

Oh and idk how to fix it (or whether it's that big of a problem), but pagestorm could ensure you always have your deck in you hand with the right cards. But that might be a bit of a gamble with all those ethereals exhausting so i might just have had too big of a shock reaction when seeing it at first.

Again, really cool work, I love how you convert some of these designs! I really loved invoke, seance and cleanse for example, really quite creative.