Experience counter

Experience counters are used by a cycle of commander in Commander 2015 to track a commander's growth in power over the course of the game. They returned in Commander 2020 with Kelsien, the Plague.

Unlike most other counters, experience counters are placed on players, rather than on permanents.

Description
Each legendary creature in the cycle has a triggered ability that grants its controller an experience counter, and a second ability that benefits from experience counters.

Because experience counters are put on players, they stay on you even if a commander dies. Additionally, multiple cards in this cycle could accumulate counters in tandem.

Ruling

 * All experience counters are identical, no matter how you got them. For example, Ezuri, Claw of Progress's last ability will count experience counters that you got from the first ability, from another ability, from proliferating, and so on.