Combust
x4
1
Dark Return
x4
1
Grenadin Drone
x4
1
Grenamender
x2
1
Slumbering Stone
x2
1
Ticking Grenadin
x4
2
Devour
x2
2
Obsidian Golem
x2
2
Vara's Favor
x3
3
Assembly Line
x2
3
Execute
x3
3
Ravenous Thornbeast
x4
4
Deathstrike
x2
4
Memory Dredger
x2
4
Soul Collector
x4
5
Colony Matron
x2
5
Umbren Reaper
x2
7
Steelbound Dragon
x1
8
Vara, Fate-Touched
x1
Fire Sigil
x7
Shadow Sigil
x12
Granite Waystone
x2
Seat of Chaos
x4
View Deck on Shiftstoned
I appreciate the help and will try to implement the suggestions as soon as possible. Don´t worry, I posted the deck here to get some information on how to improve it as it´s the first deck I built by basically throwing together what I had and forging what appeared to be fitting.
e: And I'd change the power a bit to fit in 4x Stonescar Banner and a full set of Granite Waystone
So... This is probably based on the Starter Deck the game gave you, and starter decks play mostly a midrange style. The problem is, for Stonescar, you either want to go Aggro or Control, because the archetype can't stand itself for a midrange late-game. Also, the best tip that I can give you is that Stonescar is the Faction that relies the most on unit sacrificing; take this in mind to capitalize on this idea.
If you want to go down the Aggro route, I suggest you go for a Grenadin, or a board-flood style. Dark Return, Grenadin Drone, Devour, Assembly Line, Memory Dredger and Colony Matron are good options that you already use. Some prime cards for this build are Rally, Ashara, Ruthless Assassin, Rapid Shot and Bandit Queen. In an Aggro-oriented deck, cards like Soul Collector, Umbren Reaper and Warband Chieftain may look good on paper, but actually aren't good; they are either too frail, slow, or susceptible to removal. Go wide, and go big.
Control in Stonescar isn't the best choice, but it can work. Madness is a key card in any control Stonescar (and, to some extent, Shadow) decks. Madness + Devour on turn 5 is the perfect combo for removing an opponent's threat and keeping the board clear. A lot of Shadow removal is used here; Annihilate, Devastating Setback, even Stray into Shadow. Control is not recommended because it relies on some expensive threats, like Vara, Statuary Maiden, Obrak, the Feaster etc. You could try something based on stuff like Black Iron Manacles, but I don't recommend it.
I hope you have fun, and don't feel down because of the suggestions. Try as many factions and archetypes as you can and discover what most fits you!