Blood on the Snow

The Kaldheim set doesn’t have any cards with mana costs that include {S}, but some previous sets do. If an effect says such a spell costs {1} less to cast, that reduction doesn’t apply to any {S} costs. This is also true for activated abilities that include {S} in their activation costs and effects that reduce those costs.

The {S} symbol is a generic mana symbol. It represents a cost that can be paid by one mana that was produced by a snow source. That mana can be any color or colorless.

You choose a mode for Blood on the Snow as you cast it. The last part of the effect (returning a card to the battlefield) happens no matter which mode you choose.

Snow is a supertype, not a card type. It has no rules meaning or function by itself, but spells and abilities may refer to it.

If Blood on the Snow is copied, no mana was spent to cast the copy, so you can return only a creature or planeswalker card with mana value 0.

Snow isn’t a type of mana. If an effect says you may spend mana as though it were any type, you can’t pay for {S} using mana that wasn’t produced by a snow source.