A 5-mana Sultai flier from Lorwyn Eclipsed that mills an opponent two cards every time an Elf or Faerie enters — and lets you cast one of those cards for free, once a turn, off her own tribal count.
Elf and Faerie tribal. Every creature of either type entering triggers the mill, and a wide board of them raises the mana value ceiling on what can be cast for free.
Mill and library-attrition decks. A steady two-card mill on every relevant creature entry adds up into a real threat against a deck that cares about its own library size.
Value-creature go-wide decks. Even outside a strict tribal build, a deck running enough Elves for ramp and Faeries for evasion gets meaningful mileage from the ability.
How it does in Commander
As the commander
As the commander, Maralen rewards building a dedicated Elf and Faerie tribal shell — repeated access to the mill-and-free-cast engine from the command zone is exactly the kind of payoff that deck wants leading it.
In the 99
A reasonable value piece even outside a tribal build, since most Sultai decks run at least a handful of Elves for ramp, giving Maralen something to work with.
Formats it's strong in
Elf and Faerie tribal decks. The free-cast ceiling scales directly with the tribal count, rewarding a deck built specifically around both creature types.
Grindy, long games. The mill and free-cast value compounds every turn Maralen survives, which suits a deck built to go long.
Formats it's weak in
Low-creature-count decks. With few Elves or Faeries on the battlefield, the free-cast ceiling stays low and the ability is much less impactful.
Fast, aggressive decks. A five-mana value engine that needs a turn or two to compound is a poor fit for a deck trying to end games quickly.
Synergistic cards
Elvish Mystic — A cheap, easy-to-cast Elf that both ramps and adds to the tribal count feeding Maralen's ceiling.
Bitterblossom — A repeatable Faerie token generator that steadily raises the tribal count every turn.
Lord of Extinction — A classic free-cast-off-mill target in decks built around exiling and casting big spells for nothing.
Any cheap tribal Elf or Faerie — The more of either type on the battlefield, the higher the mana value Maralen can cast for free, so going wide is directly rewarded.
Is it worth the price?
As a recent-set card, Maralen is inexpensive and a reasonable pickup for a Sultai Elf or Faerie tribal deck — low financial risk to try.