Abaddon

Abaddon the Lord of Avernus is a melee strength Hero known as one of the most versatile characters in Dota. He is most often played as a support due to powerful utility abilities such as Mist Coil, a powerful single target nuke/heal, and Aphotic Shield which absorbs a threshold of damage. Abaddon can also be an effective semi-carry or tank due to his passive Curse of Avernus which both slows his target and speeds up his allies and himself, and his unique ultimate, Borrowed Time.

Trivia

 * Abaddon's title, Lord of Avernus, is a reference to the famous crater in Italy, which was, in ancient times, believed to be the entrance to the underworld.
 * In DotA, Abaddon's third skill was originally called "Frostmourne." It was changed in transition to Dota 2 due to copyright reasons, since Frostmourne exists as a famed weapon in the Warcraft universe. Similarly, his first skill was originally named Death Coil, but was likely changed to differentiate it from the ability used by death knights in the Warcraft universe; one of Abbadon's responses when using Mist Coil references the original name.
 * In the Bible, is the name of an angel, who will rise from the Abyss and command an army of locusts.