Lenneth, Chooser of the Slain

When Lenneth, Chooser of the Slain enters the battlefield or attacks, you may pay X. If you do
so, put a +1/+1 counter on X target creatures.
Warriors you control gain First Strike, and
creatures you control with a +1/+1 counter gain
Trample and Deathtouch.
When Lenneth leaves the battlefield, if it had
any counter, return it to the battlefield at the
beginning of the next end step.
You have served me well, my Einherjar.