You can only used once in the whole battle. In battle, you will get an action called either Unholy Rites or Demonic Pact. A neutral person who has killed 50 people, will have -50 alignment and earn 5% extra gold.A neutral person who has killed 5 people, will have -5 alignment and earn 0.5% extra gold.You get +0.1% bonus percentage on gold earned for each negative point of alignment.
Negative alignment occurs when you kill a foe. A person who has 50 alignment, will damage 25 health or heal 25 Health & Magicka points.A person who has 5 alignment, will damage 2 health or heal 2 Health & Magicka points.Divine blessing is when you go to battle with someone who has a neutral or positive alignment, and heals your health and magicka equal to half of your alignment.Holy Smite is when you go to battle with someone who has a negative alignment, and does damage equal to half your alignment.In battle, you will get an action called either Holy Smite or Divine Blessing. A neutral person who has spared 50 people, will have 50 alignment and earn 5% extra experience.A neutral person who has spared 5 people, will have 5 alignment and earn 0.5% extra experience.You get +0.1% bonus percentage on experience earned for each positive point of alignment. Positive alignment occurs when you spare a foe. You get no bonus at all in this alignment. You can also check the shield in the background of the picture in the top-right corner of the Arena screen.Looking at your Character's picture above the Character Menu button (the shield background will be black and red if you are unholy, white and blue if you are holy, and silver if you are neutral.).Going to Mr Muji's Swordsmaster (He will say "Greetings, my friend.").Checking your character profile (Before battles and in the character menu).In other words it can be as high as +60, or as low as -60.
For example a Lv 6 gladiator can have a maximum absolute value of 60. The maximum absolute value of positive/negative alignment is determined by level which is Level * 10.
4 Factors affecting alignment in Swords and Sandals.