As Commander is a singleton format in which no more than one copy of each card is allowed in a deck, this means that any four Demons in your deck will enable this card
Spending three to bounce a single creature is a hefty price, and with the printing of Otawara, Soaring City, we have that base covered
Roiling Vortex is one of the best as everyone will always take one damage
In that format, it can be oppressive because its naturally cheap and can stop blockers from doing their work, or it can just get ahead on value when paired with strong ETB effects
Perhaps you'd like to see what class is like when Zombies Go to School
Gauging the exact power level of a Commander deck can be tricky , especially if you haven't gotten the chance to playtest it much yet