Eiganjo, Seat of the Empire is a rare Legendary Land card from Kamigawa: Neon Dynasty Promos (PNEO), collector number 268p. Current market price: $6.42 (foil $10.80), TCGplayer market prices via Scryfall.
{T}: Add {W}. Channel — {2}{W}, Discard this card: It deals 4 damage to target attacking or blocking creature. This ability costs {1} less to activate for each legendary creature you control.