Varchild's War-Riders — ruling 1

Paying cumulative upkeep is always optional. If it's not paid, the permanent with cumulative upkeep is sacrificed. Partial payments of the total cumulative upkeep cost can't be made. For example, if a permanent with "cumulative upkeep {1}" has three age counters on it when its cumulative upkeep ability triggers, it gets another age counter and then its controller chooses to either pay {4} or sacrifice the permanent.

Varchild's War-Riders — ruling 2

The rampage bonus is calculated only once per combat, when the triggered ability resolves. Adding or removing blockers later in combat won't change the bonus.

Varchild's War-Riders — ruling 3

In a multiplayer game, you can put the Survivor tokens onto the battlefield under the control of different players.

Varchild's War-Riders : règles, fonctionnement et interactions (MTG)

Varchild's War-Riders 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

Cumulative upkeep—Have an opponent create a 1/1 red Survivor creature token. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Trample; rampage 1 (Whenever this creature becomes blocked, it gets +1/+1 until end of turn for each creature blocking it beyond the first.)

How it works : Varchild's War-Riders

Original English text — Wizards of the Coast / Scryfall

#1October 1, 2008· Wizards of the Coast
Paying cumulative upkeep is always optional. If it's not paid, the permanent with cumulative upkeep is sacrificed. Partial payments of the total cumulative upkeep cost can't be made. For example, if a permanent with "cumulative upkeep " has three age counters on it when its cumulative upkeep ability triggers, it gets another age counter and then its controller chooses to either pay or sacrifice the permanent.
No other card is named in this ruling.
#2September 16, 2007· Wizards of the Coast
The rampage bonus is calculated only once per combat, when the triggered ability resolves. Adding or removing blockers later in combat won't change the bonus.
No other card is named in this ruling.
#3October 4, 2004· Wizards of the Coast
In a multiplayer game, you can put the Survivor tokens onto the battlefield under the control of different players.
Card named in this ruling
Survivor