It featured in some of the earliest decks in the game, it was a pivotal piece of the Sligh deck which essentially acted as the foundation of the mono red aggro archetype, and its presence has been significant in Modern from the first day of the format as it has featured in many of the formats best decks from Zoo to Splinter Twin to Jund
Merfolk Sovereign Merfolk Sovereign not only pumps your merfolk with the usual +1/+1, but it also brings some useful evasionby tapping it, you can make any merfolk unblockable for the turn
The effect is strong enough to guarantee the creation of a new Mono Black archetype in Commander
Plus, it comes back to your hand when it dies, skirting around commander tax
Back when people played for ante (and in current 5-Color Magic ), this card alone would win game after game after game
The Reaper King was tougher, because I love the way the original Jim Murray version looks, so I was afraid of trying to emulate or recreate that