Anowon, the Ruin Sage — ruling 1

When the triggered ability resolves, first you choose which creature you'll sacrifice (if you control any non-Vampire creatures), then each other player in turn order does the same, then all chosen creatures are sacrificed at the same time.

Anowon, the Ruin Sage — ruling 2

If a player controls no creatures, or if all creatures a player controls are Vampires, that player simply doesn't sacrifice anything.

Anowon, the Ruin Sage : règles, fonctionnement et interactions (MTG)

Anowon, the Ruin Sage is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

At the beginning of your upkeep, each player sacrifices a non-Vampire creature of their choice.

How it works : Anowon, the Ruin Sage

Original English text — Wizards of the Coast / Scryfall

#1March 1, 2010· Wizards of the Coast
When the triggered ability resolves, first you choose which creature you'll sacrifice (if you control any non-Vampire creatures), then each other player in turn order does the same, then all chosen creatures are sacrificed at the same time.
No other card is named in this ruling.
#2March 1, 2010· Wizards of the Coast
If a player controls no creatures, or if all creatures a player controls are Vampires, that player simply doesn't sacrifice anything.
No other card is named in this ruling.