Niko, Light of Hope

The Shard tokens are the engine, and they do two jobs from the same enchantment. Left alone, each is a slow, split-up Opt: two mana, a sacrifice, scry one and draw. A four-mana 3/4 that quietly buys two cards over the course of a game asks nothing of the rest of your deck, which is the floor. The second ability is where the card turns from value creature into puzzle box. Exile one of your own nonlegendary creatures and every Shard you control becomes a copy of it until the next end step, when the original returns to the battlefield. Crucially, the Shards do not re-trigger the copied creature's enters ability, because they are already on the battlefield when they take on its printed abilities. What they inherit is what they can do while wearing its face: any activated ability the copied creature has, the Shards can activate too, tapping or sacrificing themselves to fire it multiple times in a turn. The original, meanwhile, sits safely in exile until end of turn, so it is the Shards doing the impersonating, not a battlefield full of duplicates alongside the real thing. That same-turn exile is the pivot: it doubles as a dodge from a spot-removal spell as readily as it enables a copy loop. Which mode you get depends entirely on the nonlegendary creature you aim it at, and the card's ceiling scales with whatever activated ability that creature is hiding.