kingholldder

do you have that card? yes or no?

what happens if a hellkite tyrand attacks you? with something like sneak attack.
or
furnace dragion comes into play?
or
merciless eviction is played?
or serenity or Creeping Corrosion or one of those many cards?

i dont see it. i see this is a good deck but you have no removal and almost no flying.
i would add search cards becous its a combo deck. you can F it all up if you miss just the right cards.
if you dont want to add those cards try a sideboard.

can you use his ability is your upkeep? or before that?

use doomed traveller. silverblade paladin, thalia, fiend hunter, avacyn pelgrim, champion of perish, scorned villiger, gavony township, angelic overseer, odric, avacyn (not to fast i know), sunpetal grove, oblivion ring, cathedral sanctifier, elite vanguard, gideon's lawkeeper, knight exemplar (use with soldiers), knight of the white orchid, loyal centry (realy good combo wth avacyn's collar), masako, mentor of the meek, mirran crusader, mother of runes, silence, precinct captain, sworn defender (since it has +1 by the collar it is a cheap kill), thraben doomsayer, true believer (somewhat sideboard), aysen crusader (more for soldiers).

Try this!
(not all of this afcourse.)

only 5 cards what are not rare! (two of them are basic lands)

Could it work to put a Liliana of the veil in? in most gravepower decks what has black it is handy to have a liliana. (at least what i think)
afcourse you wil have to remove a card from your deck and that aint to easy, but i would go for one gravecrawler.
why gravecrawler? becouse the thing with him is that you have four of them and if you want to mass sacrifice you need only one. you do not have to be afraid (only a bit) for removal becous you can cast him from the graveyard but four still is a bit much.

irealy like this deck a real lot, i use gravepower my self and it aint costing to much. look at number two of the most liked deck. ($560)

thanks for the tip.