If one or more other creatures enter the battlefield under your control at the same time that Elas il-Kor enters the battlefield, its second ability will trigger for each of those other creatures.

If one or more other creatures you control die at the same time that Elas il-Kor dies, its last ability triggers for each of those other creatures.

In a Two-Headed Giant game, Elas il-Kor’s last ability causes the opposing team to lose 2 life.