For ten loyalty, you get an emblem that reads, Whenever an Artifact is put into your graveyard from the battlefield, return that card to the battlefield at the beginning of the next end step. Basically, it gives you a weird version of immortality for all of your Artifacts, and its an absurdly hard thing to beat
Cheating a 6-mana artifact into play is hard but doable
She also has decent toughness, making her a solid blocker if you need time to get your control or combo pieces in order
You want to make sure that you are able to cast all of your spells, and cast them on time
They get pumped by +1/+1 in size making this a cross between an on-curve Mana Rock and Lord effect for your creature type
Grothama is an interesting leader, possibly handing out card advantage at the cost of other creatures