Ascent is 1 domain 2 flux. Returns creature to players hand.
Negate is 1 domain 2 flux. Removes ENTITY just played from game, but gives flux back to controller.
Lysis is 2 domain 4 flux. Straight up kills creature.
This is how I see these cards and their value:
Ascent is a two-sided card. It can be good and bad. Your creature just got hit for death damage? Ascent it back to your hand and play it later. Good for saving those tougher creatures, bad because you have to play it again (and they're not cheap). OR you see a baddy come after your stuff. You return it to your opponents hand only to see it again in a round or two. Good that it saved you this round, bad that you have to face it again. For the cost, I'd say Ascent is a good balanced card.
Negate is just like a counterspell, except this counterspell gives the flux back to you. While it can be very aggravating, at least you didn't just lose all that flux you spent. This card requires the summon to be in sight and cast immediately next turn. While those are limiting factors, I believe the cost is just too low for the ability. It should be at least two domain in my opinion (which isn't hard for Mountain).
Lysis is a straight up kill it card. Creature dies, makes a corpse. Now the corpse is something that can be benefited by the Dark Legion cards like Journeyman Necromancer, Death Mark, Carrion Feeder, and Gather Spirits (I'm sure there's more). I think the cost of the card is pretty comparable to some of the costs of these other cards. Sure it's always annoying to have your big cost creature just suddenly die, but hey they're the Dark Legion, they can do that.
Now limiting Lysis to your area (as Attrition) is something that would hurt the card, what if you have a Spaf's Greatbow firing down on you from afar? Well it's not in your area, sorry you just have to deal with it.
Limiting it to something adjacent... well just read above, but only even more limited.
Limiting it to something just cast? Then lower the cost of the card to a little more than Negate and see how you like it then, too, hmm?
Returning it to your hand is already a card.. it's called Ascent. Dark Legion would never give you the creature back though, that's just not their style. It has to die.
Hope this might help see a different view point.
