Sindri, Nissa’s Protégé

Landfall- Whenever a land enters under your control, you get {e}.
Whenever you cast a creature spell, you may
pay X {e}. If you do, that spell’s mana cost is reduced by X. Only colorless mana can be reduced this way.
It’s been many years since Nissa visited Kaladesh, but her impacts will never be forgotten.