Destined // Lead

If another effect allows you to cast a split card with aftermath from a graveyard, you may cast either half. If you cast the half that has aftermath, you'll exile the card if it would leave the stack.

As blockers are declared, any creature that's tapped or affected by a spell or ability that says it can't block doesn't block. If there's a cost associated with having the creature block, no player is forced to pay that cost, so it doesn't block if that cost isn't paid.

Each split card is a single card. For example, if you discard one, you've discarded one card, not two. If an effect counts the number of instant and sorcery cards in your graveyard, Destined // Lead counts once, not twice.

A spell with aftermath cast from a graveyard will always be exiled afterward, whether it resolves, it's countered, or it leaves the stack in some other way.

Lead doesn't give any creatures the ability to block the target creature. It just forces those creatures that are already able to block the creature to do so.

All split cards have two card faces on a single card, and you put a split card onto the stack with only the half you're casting. The characteristics of the half of the card you didn't cast are ignored while the spell is on the stack. For example, if an effect prevents you from casting green spells, you can cast Destined of Destined // Lead, but not Lead.

If another effect allows you to cast a split card with aftermath from any zone other than a graveyard, you can't cast the half with aftermath.

Split cards with aftermath have a new frame treatment—the half you can cast from your hand is oriented the same as other cards you'd cast from your hand, while the half you can cast from your graveyard is a traditional split card half. This frame treatment is for your convenience and has no rules significance.