Serpent Warrior — ruling 1

You can cast this if you have less than 3 life, since the life is lost as an effect and not a payment.

Serpent Warrior : règles, fonctionnement et interactions (MTG)

Serpent Warrior 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

When this creature enters, you lose 3 life.

How it works : Serpent Warrior

Original English text — Wizards of the Coast / Scryfall

#1October 4, 2004· Wizards of the Coast
You can cast this if you have less than 3 life, since the life is lost as an effect and not a payment.
No other card is named in this ruling.