When Thalia's Lieutenant enters the battlefield, put a +1/+1 counter on each other Human you control.
Whenever another Human enters the battlefield under your control, put a +1/+1 counter on Thalia's Lieutenant.
If Thalia’s Lieutenant enters the battlefield at the same time as another Human, each of Thalia’s Lieutenant’s abilities will trigger. You’ll put a +1/+1 counter on both cards.