That's pretty strong
This card is stacked, considering it only costs one black and one white mana , oh, and it also comes with sneak, which can be activated for the same cost, guaranteeing combat damage if not countered, and great if you've already got three Ninja creatures on the board
1: These cards arent playable in your main deck, usually because theyre too situational
Avoid fights whenever possible, as your characters arent great at challenging, unless you use the Challenger and strength effects
Teval, Arbiter of Virture is here to give a tricky build condition that keeps you conscious of your life total
The rub here is you have to pay that life, so you'd need a way to keep the storm going to protect yourself