The ability gained by the land triggers at the beginning of the upkeep of the land’s controller, not the beginning of the upkeep of Obsidian Fireheart’s controller. The player who controls the land at the time the ability triggers is the one who’s dealt damage.
As the reminder text indicates, whether the targeted land has the triggered ability that’s been granted to it depends only on whether it has a blaze counter on it, not on whether Obsidian Fireheart is still on the battlefield.
A land with a blaze counter on it is an illegal target for this ability. You may activate the ability targeting a land, then activate the ability in response to itself targeting the same land. Although the first ability to resolve will put a blaze counter on that land, the second ability to resolve won’t resolve.
Last observed on Scryfall 2 months ago at $6.72. Over the trailing 90 days the price moved between $0.02 and $6.72 across 57 observations. Cross-checked across TCGplayer, eBay sold, Cardmarket EU, and Star City.
This printing is one of 3 catalogued treatments from ZEN — the lineup includes Foil and Nonfoil alongside the standard finish. Across our catalog the Rarix library tracks every variant in the same family so collectors can compare price, scarcity and demand inside a single lineage.
Card #140 of *Zendikar*, the set that shipped alongside the October 2009 Zendikar release.
Card type: Creature — Elemental, color identity red, printed at mythic. Mythic rares historically land in roughly one out of every eight boosters at standard print densities. Mana cost: {1}{R}{R}{R} (4 converted).
Legal in Modern, Legacy, Vintage, and Commander.
EDHrec ranks this card #16,721 in Commander, putting it in the fringe-play tier of the format's playable pool.
Illustrated by Raymond Swanland. Rarix catalogs 886 other cards credited to this artist.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Raymond Swanland
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
If all blaze counters on a land are moved to a different land, the triggered ability doesn’t follow them. The first land no longer has the ability because it no longer has a blaze counter on it. The second land doesn’t have the ability because Obsidian Fireheart didn’t target it.
If a land ends up with more than one blaze counter on it (thanks to Doubling Season or Gilder Bairn, for example), the ability still only causes it to deal 1 damage to its controller each turn.
