Alaric dies in Damons arms In The Departed, when Damon tries to hide Klaus' body, Alaric gets Jeremy to disclose Klaus' location, and tries to kill Damon.

What happened to Alaric in Season 3 Episode 20?

In the cemetery, Elena pulls the stake out of Alaric. Esther tells her that when he revives that he may be his old self so she should say her goodbyes. ... Alaric appears behind Esther and stabs her with the stake, killing her. Alaric has awoken as his old self and doesn't know what has happened to him.

How does Alaric get killed?

Damon stabbed Alaric with a stake in season 1 when confronted about killing the hunter's wife. In season 3, his human self was transformed into an original vampire upon his death, though this darker version of Alaric met his end too.