"If you hire a sell-sword, you'd better watch your back. Hire me, and I'll watch it for you."

Kazandu Blademaster

First strike, vigilance
Whenever this creature or another Ally you control enters, you may put a +1/+1 counter on this creature.

The List

Zendikar

First strike, vigilance
Whenever Kazandu Blademaster or another Ally enters the battlefield under your control, you may put a +1/+1 counter on Kazandu Blademaster.

This ability triggers on this creature entering, so it will enter with its unmodified power and toughness, and then receive a +1/+1 counter a short time later. It does not enter with the +1/+1 counter already on it.