|First appearance||Under the Bridge, Part 1|
|Known ability||Water mimicry|
|Occupation||Prison transport bus guard|
On the bus Donald laments that he has wasted his entire life. While Donald keeps watch, one of the prisoners uses his ability in rage at another, killing those on the bus, including the bus driver, causing it to crash and explode. After the explosion of the bus, Donald (as the sole survivor) is visited in hospital by Nathan Petrelli, who wants to talk to him about what happened on the bus.
In the Memphis General Hospital, Donald reviews a sheet of paper. He tells Nathan Petrelli that he doesn't know how he survived the bus crash without a scratch on him, but Nathan knows that someone on the bus had abilities that killed everyone except for Donald. Nathan asks Donald to join a task force he has created to take down these evolved humans, but Donald says that he is not interested. Nathan tells Donald to sleep on it and he'll be back in the morning. Donald returns to his hotel room, planning to leave the place as soon as possible. He asks himself what he has gotten into, and further scorns himself for talking to himself. Donald then relives the scene on the bus, and later imagines what would've happened if he had told Nathan that he himself had an ability. Just then, Nathan's bodyguards break into the room, having learned he is an evolved human thanks to DNA evidence. Donald, however, attacks the bodyguards, spraying a massive torrent of water at them. An agent sprays a substance in Donald's face, which subdues him and renders him unconscious. As he starts to faint, Donald's body begins dissolving into a watery puddle. Nathan then states that Donald is the Mississippi River's problem now.
Donald Essex has displayed the ability to turn himself into water. With this ability, he was able to survive Perrin Crocker's spikes by turning his chest into water. When he transforms his arms into water, he can generate more water from his arms and fire them at people. After he was subdued by Nathan's agent, his entire body begins dissolving into water, which is eventually dumped into the Mississippi River.
- For other uses of Donald, see Donald (disambig).
Please refer to Theory:Donald Essex for fan-created theories and other speculation.