

This can't be played from the EX area.
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: Evolve this.
Rush.
Whenever a follower on your field evolves, place a fighting spirit counter on this in your EX area. Then, if this has at least 2 fighting spirit counters, you may summon it. If you do, evolve it.
Put this into its owner's EX area.
QCan I summon Kagemitsu, Lost Samurai from my EX area with Amelia, Sunny Paladin's activated ability?
AYes, you can. Note that Kagemitsu, Lost Samurai would retain its fighting spirit counters if summoned this way, and it would not evolve, as its automatic ability would not trigger.
QIf a card leaves the field, does it lose all its counters?
AYes, it does.
QIf I summon this follower with its automatic ability, can I choose not to evolve it even if there is a Kagemitsu, Lost Samurai in my evolve deck?
AYes, you can.
QIf my EX area is full, how do I resolve this follower's Last Words ability?
ASince your EX area is full, this follower would remain in the cemetery.
QDoes this follower's "Whenever a follower on your field evolves" ability only trigger while it's in the EX area?
AYes, that's correct.