This creature has two abilities, and those two abilities are super powerful when working together
This is at its best in stax decks leveraging cheap creatures like Collector Ouphe and Archon of Emeria or token decks building out massive numbers of 1/1s
This Rogue may be really agressive by itself and even more with a sword on its hands
We also have The Soul Stone, the big powerful collectible of the set, and probably a sign that we aren't going to be finished with Marvel for an awfully long time
Once transformed, it becomes Polukranos, Engine of Ruin, which is a 6/6 with reach and lifelink and reads: Whenever Polukranos, Engine of Ruin or another nontoken Hydra you control dies, create a 3/3 green and white Phyrexian Hydra creature token with reach and a 3/3 green and white Phyrexian Hydra creature token with lifelink. Even without any other hydra creatures, the fact this card will split into two is amazing - but with some clever deckbuilding, it could make your deck unkillable