When entering battle (moving towards an enemy, possibly attack move)
"This would be easier if we had fuel rod guns."
When retreating battle (moving away from enemy)
"Flee! Run for your lives!"
After killing an enemy (UNSC)
"I hit him? I hit him! Weee!"
"Die human!"
"They do bleed red."
After killing an enemy Grunt
"Die traitor!"
"Sorry!"
After killing an enemy Elite
"Ha! We killed the Elite! They're all gonna die!"
After seeing a comrade Grunt killed
"Why do we even try?"
"Poor <insert random Grunt name>, I knew thee well!"
After seeing a comrade Elite killed
"He's dead! We're all doomed!"
After encountering an enemy Spartan or Zealot (after taking damage, but not being killed by a Spartan or Zealot)
"Spare me!"
"They made me do it! I didn't want to kill all those people!"
"Don't shoot! I'm on your team! I promise!"
"Why does everyone hate me?"
After being killed
"The horror! The horror!"
After being killed by a Spartan or Zealot
"What did I ever do to you?"
Suicide Grunt
"If I go down I'm taking you with me!"
"GAH! Its stuck to my hand!"
"Suicide Grunt!"
"Tora tora tora!"
I like pi.