When Niko enters, create two Shard tokens. (They're enchantments with "{2}, Sacrifice this token: Scry 1, then draw a card.") {2}, {T}: Exile target nonlegendary creature you control. Shards you control become copies of it until the next end step. Return it to the battlefield under its owner's control at the beginning of the next end step.

Constellation — Whenever an enchantment you control enters, you may have this creature become a copy of another target creature, except it has this ability.

All permanents are enchantments in addition to their other types.

When Niko Aris enters, create X Shard tokens. (They're enchantments with "{2}, Sacrifice this token: Scry 1, then draw a card.") +1: Up to one target creature you control can't be blocked this turn. Whenever that creature deals damage this turn, return it to its owner's hand. −1: Niko Aris deals 2 damage to target tapped creature for each card you've drawn this turn. −1: Create a Shard token.

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.