Asgea, Scholar of Worlds

Whenever mana is put into your mana pool by another spell, you get an experience counter.
At the beginning of your upkeep, you may put X {w}, {u}, and/or {g} into your mana pool where X is the number of experience counters you have.This mana doesn't empty from your mana pool
as steps and phases end.
"A world to live, worlds to learn."