Cheapest priced copy (Dominaria United Commander): $1.99 at Card Kingdom, near mint, their price list as of .
Basim, Master Assassin 
Ramses, Assassin Lord
Legendary Creature — Human Assassin · 4/4 · Rare · Secret Lair Drop · #1560
Deathtouch
Other Assassins you control get +1/+1.
Whenever a player loses the game, if they were attacked this turn by an Assassin you controlled, you win the game.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $1.99 to $29.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dominaria United Commander | 39 | Rare | $1.99 | $2.99 |
| Dominaria United Commander | 61 | Rare | — | — |
| Secret Lair Drop (Basim, Master Assassin) | 1560 | Rare | $27.99 | $29.99 |
4 rulings from Wizards of the Coast
- 9 September 2022For the last ability to trigger, an Assassin you controlled must have attacked the player. Attacking a planeswalker the player controls won’t count.
- 9 September 2022Similarly, if an Assassin enters the battlefield under your control attacking a player, that creature didn’t “attack” and won’t cause this ability to trigger.
- 9 September 2022As long as that player was attacked this turn by an Assassin you controlled, Ramses, Assassin Lord’s last ability triggers when that player loses the game for any reason, not just due to combat damage. This is true even if the Assassin is no longer on the battlefield, no longer under your control, or no longer an Assassin at the time that player loses the game.
- 9 September 2022If you attack an opponent with a non-Assassin creature and that creature becomes an Assassin after attackers were declared, that player was not “attacked” this turn by an Assassin you controlled.