When the echo ability resolves, you may pay or choose not pay. The first option means Shah of Naar Isle stays on the battlefield and its last ability triggers. The second option means Shah of Naar Isle is sacrificed.

If you have multiple opponents, each one in turn order chooses whether or not to draw cards, and if so, how many to draw (from zero to three).

If you use Thick-Skinned Goblin’s ability to pay instead of Shah of Naar Isle’s echo cost, the Shah’s last ability will trigger.