Anger was an emotion. In its deepest form, anger could turn to rage.

In response to negative emotions such as feargrief and anger, humans once took medication in the future, to remove and override them. (AUDIO: Harvest of the Sycorax)

The Tenth Doctor once stated that he could get "so much more [angry]" than he was currently when he discovered that a Floof had killed Kathy. (PROSE: Corner of the Eye)

An emotional amplifier uncovered by Torchwood Three amplified anger into rage - so much so that Gwen Cooper feared she could have killed Rhys Williams. (PROSE: Slow Decay)

Tanya Adeola fed the Lankin anger, not grief, poisoning it, which left it in a weakened state. (TV: Nightvisiting)