Aye, like most first decks this one is suffering from a lack of focus. Stalkers require a lot of dedication to work, and while Bone Wall is the best rush-stopper shield out there, you'll usually want Drain Lives to make good use of it in this duo. It's more practical to run Stalker decks with Death mark and the rest being a Darkness domination deck. This is the one I usually run for fun in PvP1 now and then:
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52u 52u 52u 52u 52u 52u 5uk 5uk 5uk 5uk 5uk 5uk 5uk 5uk 5uk 5uk 5uo 5uo 5up 5up 5uq 5uq 5uq 5ur 5us 5us 5us 5us 5us 5us 8pkThe Darkness stall gives the Stalkers time to do their job, and Steals are essential since they only get 1 attack. Drains can be used for direct damage in an emergency, but are mostly for CC to survive.
Your deck, however, is closer to a standard Deathrush, which is 14 Bone Pillars, 4 Bone Dragons, 6 Mummies and 6 Poisons. It's a decently fast, very consistent rush that performs averagely in Bronze, but very well in PvP1 and against AI3. Arsenic fits well into the deck of course, but there's no general consensus on what to take out for it, so experiment as you see fit.
I'd like to advise you to plan out a deck that will farm your intended target well before upgrading cards. As I'm sure you can see for yourself, Stalker is a terrible upgrade. The rest of your upgrades are good, though Eclipse usually requires a complete Monodark deck to be worth it.
