Nya, the Water Ninja

Vigilance, islandwalk (This creature can't be blocked
as long as defending player controls an island.
When Nya enters the battlefield, all blue
creatures you control get a +1/+1 counter.
If The Samurai is on the battlefield, Nya gets
-0/-1 and, The Samurai gets +0/+1.
{2}: Add {u} to your mana pool.