Who said "Mercy is for those who lack conviction."?

This quote is attributed to Darth Maul.

Mercy is for those who lack conviction. - Darth Maul

"Mercy is for those who lack conviction."

Darth Maul Justice

"At last we will reveal ourselves to the Jedi. At last we will have revenge."

"The suffering you feel now will forge you into something greater."

"Patience is the weapon of the truly powerful."

"I am darkness given form, and I hunger for your destruction."

"Justice must always prevail."

"You think I'm just some animal?"

"Fighting for what's right never gets easier."

"Justice is worth fighting for."