Cheapest priced copy (New Capenna Commander): $0.69 at Card Kingdom, near mint, their price list as of .
Custodi Lich 
Creature — Zombie Cleric · 4/2 · Rare · New Capenna Commander · #244
When this creature enters, you become the monarch.
Whenever you become the monarch, target player sacrifices a creature of their choice.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.69 to $8.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Conspiracy: Take the Crown | 41 | Rare | $0.79 | $8.99 |
| New Capenna Commander | 244 | Rare | $0.69 | — |
4 rulings from Wizards of the Coast
- 23 August 2016Abilities that trigger whenever you “become the monarch” trigger only if you aren't already the monarch. For example, if you are already the monarch as Custodi Lich enters the battlefield, its last ability won't trigger.
- 23 August 2016The game starts with no monarch. Once an effect makes one player the monarch, the game will have exactly one monarch from that point forward.
- 23 August 2016If the triggered ability that causes the monarch to draw a card goes on the stack, and a different player becomes the monarch before that ability resolves, the first player will still draw the card.
- 23 August 2016Being the monarch carries two inherent triggered abilities. “At the beginning of the monarch's end step, that player draws a card” and “Whenever a creature deals combat damage to the monarch, its controller becomes the monarch.”