Whenever a creature you control with power 2 or less enters, you get an experience counter. At the beginning of combat on your turn, put X +1/+1 counters on another target creature you control, where X is the number of experience counters you have.

Vigilance, haste Kelsien gets +1/+1 for each experience counter you have. {T}: Kelsien deals 1 damage to target creature you don't control. When that creature dies this turn, you get an experience counter.

Whenever another creature you control dies, you get an experience counter. At the beginning of your end step, choose target creature card in your graveyard. If that card's mana value is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.

Minthara has ward {X}, where X is the number of experience counters you have. At the beginning of your end step, if a permanent you controlled left the battlefield this turn, you get an experience counter. Creatures you control get +1/+0 for each experience counter you have.

Converge — Search your library for a creature, instant, or sorcery card with mana value less than or equal to the number of colors of mana spent to cast this spell, exile that card, then shuffle. You may cast that card without paying its mana cost.