A-Dungeon Descent

The Arena rebalance is why this version exists, and it is purely a buff: the paper original asked and entered the battlefield tapped, while this one drops the activation to and comes into play ready to work. The legendary-creature requirement was there all along, and it is what keeps the venture engine honest. A repeatable venture stapled to a colorless mana source is generous, so the tax is not the mana or the tap but the demand that you keep legends on the board to feed it. That rewards a legend-dense build where a spare commander or planeswalker-adjacent body standing untapped after combat is a resource rather than a liability. The sorcery-speed clause keeps the venturing on your own turn, so there is no instant-speed dungeon acceleration, and tapping the legend forces a choice between its own activated ability, an attack, and another step deeper. What the card really does is convert venture from a one-shot spell trigger or a combat trigger into a land activation you can lean on every turn, walking a deck down the Lost Mine of Phandelver or the Dungeon of the Mad Mage without spending cards to do it. The land taps for colorless on its own, so the venture line is upside layered onto an unremarkable mana rock disguised as a land; the legendary tap is the toll that stops that upside from being free.