Quite OP. Compare this card to Immortal. For a better cost to damage ratio, you have the same unkillable creature but also with a built in creature control and creature booster. Running simply off your mark you can turn devourers into 7 force killers and exagerate this even further under the effects of eclipse. The only two cards capable of stopping this are fire shield and thorn carapace both of which see less than normal play and are easily countered with another darkness card steal allowing you to ghostify the opponents creatures and use the shield as your own CC. To add insult to this you also have a card generator, the Haunted Mansion which pops these out.
How to fix it?
Firstly you need to decide what aspect of the ghost you want to identify with most. Is it the Immaterial creature? If so then you need to strip the other effects that break its potential.
To me, a ghost is the residue of a sentinent creature going about its task or patterns it had in life. It causes fear in those it engages with and being intangible will move past barriers that would stop normal creatures. They don’t appear in the light.
How about a 1/1 and a 3/1 momentumd and immaterial creature for 4 with the power to nightmare itself into the opponents hand?
Damn he knows his Darkness cards well. 8)
