Perhaps Crucible Coliseum is the best place to prove your power. In Crucible Coliseum, everyone is your enemy, regardless of faction.

Venture into the Crucible Coluseum and kill 10 other combatants.

If you prove your power and return to me, I'll help you extend your Greater Stigma Slot with a Mysterious Stigma.

Player: Accept.

Excellent! With your power, you'll be able to handle the Greater Stigma with ease.

I'll give you a Mysterious Stigma, so please hold it in your arms for a while, allowing it to absorb your energy.