We are first introduced to Achardor in Imlad Lalaith before the Hidden Guard crosses Anduin, and we get to see him in many instances during Book 9, but we never see him outside those instances.
Vol. 2, Book 9:
During the Plans of the Golden Host instance you have the chance to ask him some questions.
Tell me about yourself.
- 'A short time ago I visited the halls of Thranduil and spent the days feasting and conversing with our cousins in northern Mirkwood. My brother Faengris was slain while I was away.
- 'Mazog will not leave my sight. If he gives me even one reason to do so, I will end him. The Lady Galadriel must agree with this, for why else would she speak on my behalf to Lord Celeborn?'
I have met Núrelleth.
- 'I know you have, and you have my thanks for easing the burden of my brother's widow. She may be content to remember Faengris, but it is not enough for me. I desire vengeance.'
What do you think of this mission?
- 'I think it is foolhardy to return Mazog to his allies, no matter how many dwarves might be saved.
- 'But I doubt also that Mazog will ever reach Dol Guldur alive. He will surely try something on the journey, and I, Achardor, will be there to end his life. I will delight in my vengeance, and shed no tears for a plan unrealised.'
We get to ask him some more questions when the Hidden Guard is trying to decide which way is the safest
How are you feeling?
- 'I am angry, as all of us should be! Already too many Elves have died on this foolish errand, and one too few Orcs, if you ask this Elf's opinion. How many more of our party must perish before we abandon this foolish expedition?'
You believe our road lies through Emyn Lûm?
- 'I do, and I cannot understand why these others, these friends, do not see why that is the best route for us to take! The sooner we reach the fortress, the sooner we may deliver Mazog to his allies and be done with this ridiculous mission! I am finished with roundabout ways. Let us fly straight as an arrow, and be done!'