Like most Magic: The Gathering cards, the value of Angelic Skirmisher depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Gatecrash)
And of course, any master assassin knows that a haystack is the most flawless escape plan, so that makes an appearance too
And your stuff is very much dying
Like set boosters, the exact distribution in collector's boosters changes from set to set
Unlike English packs, which guarantee at least one rare card, Japanese packs do not always include a rare but often feature higher-quality printing, sharper edges, and a more vibrant finish
A single-player campaign could very well be added in the future