If Alisaie Leveilleur and Alphinaud Leveilleur are your commanders, your deck may contain cards with white and/or blue in their color identity, but not black, red, or green
In that case, the ability will still resolve and you'll have the opportunity to collect evidence 9
The starting stats are bad, but this can quickly grow and it's attack trigger can help aggro decks get in for lots of damage early
It doesnt do anything spectacular, but does provide some neat deck-building choices to work around to use effectively
As it stands, however, Liliana is probably the better option
Basic cantrips like Consider and Thought Scour fill this role nicely, fueling your graveyard early in the game