1:I thought it was OP when i first saw it.Its not that good since theres alot transform around to weaken deathknells summoning and since arcanyst abyssian is rather weak earyl on its very possible to finish the game before deathknell becomes an issue.
2:Arcanyst abyssian.I dont face it often(diamond 3) but currently run it myself
3:I like the way it supports abyssian lategameking idea. It needs buildup and cant be ramped into but once it gets out the game is pretty much over unless your opponent kills you next turn(or unless lyonar plays aperions claim,or unless vanar goes for gravity well,ghost seraphim,flawless refelction to make a board with similar power)I dont like the art at all…it doenst look like the ruler over death that it should be.
4:Im happy with it…the archetype is in a good spot right now in my opinion.Death knell is a very important card for it…without it there would be little to no reason tor abyssarcanyst over vanarcanyst
For Nightshroud:
You wont see someone in diamond and above running it in an abyssarcanyst deck(and those who play this deck are few to begin with).Why?Its too inconsistent and expensive.You already have a problem with a compareably weak earlygame so a 5mana card that does almost nothing once its played isnt good(and if you get so many arcanysts early on that its actualy good to play you won anyways most of the time)
If you include it as a finisher its unrelyable because the spawnorder is luck based.You could get very lucky and summon nightshroud last for a massive healthswing…or summon him first for almost no impact.
Not to mention that death knell wins the game anyways once hes summoned unless your opponent transformed your most important arcanysts (in which case nightshroud wont do much either),kills you next turn(luck based if nightshroud helps you against that),or goes for 1 of the 2 above mentioned plays