All Will Be One
Enchantment
Whenever you put one or more counters on a permanent or player, this enchantment deals that much damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.
The Invasion Tree broke through the Blind Eternities and sent Phyrexian perfection coursing across the Multiverse.
Chris Rahn
Rulings
All Will Be One's ability will trigger any time you put one or more counters on a permanent or player. This might be due to a spell or ability resolving, a permanent you control entering the battlefield with counters, or combat damage from a source with toxic, infect, or wither.
(wotc • 2023-02-04)
If more than one creature with toxic deals combat damage to a player at the same time, those counters are placed as a single event, and the ability triggers one time.
(wotc • 2023-02-04)
Rulings
All Will Be One's ability will trigger any time you put one or more counters on a permanent or player. This might be due to a spell or ability resolving, a permanent you control entering the battlefield with counters, or combat damage from a source with toxic, infect, or wither.
(wotc • 2023-02-04)
If more than one creature with toxic deals combat damage to a player at the same time, those counters are placed as a single event, and the ability triggers one time.
(wotc • 2023-02-04)