The Soul Stones harness ability is a bit overblown given the massive set-up cost, but it's all gravy on a massive upgrade to Charcoal Diamond, and an indication that the other colors will be getting some improved mana rocks soon enough, probably a few as early as Marvel Super Heroes next year
Now that Vadrik is nice and buff, its time to sling some serious spells
You can wield spells (Sorceries and Instants) that allow you to destroy creatures, trigger various one-time effects, or most important of all, draw more cards
Of note: Fact or Fiction during their end step cant be hit with an alternate-cost Force of Negation because its still their turn
It's likely to catch removal, but if it sticks you'll have a rapidly growing flier that makes your opponents sacrifice a nonland permanent with every attack
Although fight is now a keyword action, not all cards that use this style of mechanic use the fight keyword