Claim of Erebos

The math here is the whole problem. Two mana for the Aura, then another two-plus-a-tap every turn to bleed a single player for two life, is a rate that belongs to a much slower era of design, when grinding an opponent out one increment at a time was an acceptable plan. The activated ability points only at a player, so there is no creature-removal flexibility hiding in the text: the loop exists to chip away at a life total, nothing more, and the cost is steep enough that it rarely outraces the clock it sits on. What it really represents is the enchantment-matters direction black was being nudged toward in this period: cheap Auras that turn an ordinary body into a slow incremental engine, priced under the assumption that the enchantment count itself was a reward worth paying for. The body still has to survive and untap before it pays anything back, which compounds the inefficiency for a deck trying to win on its own merits. As a standalone, it asks too much mana per point of life lost for the effect to matter; as a cog in a deck that cares about how many enchantments it controls, it is a contributor to that count rather than a payoff in its own right.