So...

This Unknown man is Cessiar...then who are the other Unknown men?

The unknown man isn't just one. They're actually a group of people who oppose the shamans. Ruairi is counted as one of their ranks. Later Tarlach is found to be one of them. Their goal later on in episode 10 is to sacrifice Millia in order to bring Macha back, which they did, when Tarlach restored the Lia Fial from g3. Cessair is one of the more influential people of them. Another would be Quasar's Heart who is also a dual wielding girl. They each work together but have their own agendas. They oppose the shamans who wish to keep the dragons under control.

Why do they want Macha and the dragons? O-o

As miyuna said, there are multiple unknown map. The one in particular seen in G17 is NOT Caesar for sure. Reason being. [1] Caesar is the right one, you can tell she's different because, well, she's female so she has more obvious breasts, on her model too, and her portrait has no scarf and different decorations.

Then, who IS the middle one, and who's the white one?

The white one unmasked is Tarlach. He's wearing the same colors in his older G18 image on his profile page.

Here's something I didn't catch: How is Tarlach able to leave the Altar of Druids?

Has something to do with the purple circular thing Ruairi gives him.

Let me guess, he stole it from Millia or us?

He obviously obtained it before our start of G18.

Ah, of course...

Oh yay, Tarlach becomes a bad guy!

The middle one could be Ruairi, or it could be a random member of their organization. Also, I don't know if Quasar is one of the middle or if she has an icon similar to Caesar Heart's.

According to Mabination's translation of an official map of the relationships, here, Quasar seems to be the name of the organization that opposes the masked men.

Then again, they labeled the generic subordinate masked man as Cessair, and the female superior masked man as a generic, so I guess we can't even trust KR Nexon to get it right.

So this:

has absolutely no reason to exist what so ever?

I may be wrong about Quasar being an actual member, but Cessair is DEFINITELY female, we see her with the robe off later.

I have a question: Do we fight any of those major "Unknown Men"?

We fight Tarlach, I don't know about Ruairi or Cessair.

What the hell, we helped him and now he turns on us!?

I really don't want to spoil much, so I kept my mouth shut...

But the reason Tarlach is helping Ruairi is a much much deeper reason than simply "opposing" us.

Just say it dammit D:

All I know is Tarlach is helping Ruairi find out the truth about Triona's death. Technically WE are the bad guys in this scenerio.

Dammit, again? They should have questioned their "precious goddess".

I'll give you some storyline hints:

1) Ruairi is looking for someone, should be obvious 2) Ruairi is sent to kill Shamala for the XX Clan 3) However, Ruairi is unabled to do so because he still has "good" in him 4) We're not the only ones who are experiencing a corrupt added soul phenomenon, in fact, you find out later that it is only Milletians being affected. 5) The artifact that Shamala and Akule is holding allows one to clear possible influence and curses (hint hint) 6) Ruairi feels betrayed by Millia after she takes him to the Shamans (his enemies) to get healed, though in the process, she never reveals who he is to the Shamans. This prompts Ruairi to turn to Uladh again for a reason 7) The giants are responsible for something 8) Remember the giant civil war? 9) Every Masked Man (at least the named ones) has a very own persona agenda 10) Even though you are the Golden Dragon Conductor, you are still connected to the dragons, yet why does Ruairi have the cursed dragon arm?

Piece it out together. =)

What Giant civil war?

I wanted to ask that, but wasn't it about Kirine and Krug secretly ordering Taunes' men to abandon him or something? Then, when he comes back, Krug tries to arrest him because he refused to lead another assault on the elves.

I'll recap the giant civil war:

A long time ago, Krug's father waged war with the elves. It was a bloody war that lasted a while, but during that time, Krug's father died. With the missing throne, there were people who fought for the crown, not just Krug. Among these people were Zeder's father, who was largely popular. He wanted to end the war and usher in peace with the elves. However, Krug, disliking that Zeder's father was opposing everything that his father stood for and his popular support nearing him to the crown, had Zeder's father assassinated. With Zeder's father dead, he took the throne without question and became the king. He then continued his father's campaign to annihilate the elves and the war. However, he knew that Zeder's father had a son, namely Zeder, so he had Wanst adopt Zeder to raise him and keep him under surveillance in case he were to end up like his father and fight Krug for power. Up to this day, Zeder, fully aware of what happened, is secretly sharpening his blade of revenge.

Mm, how come we don't have recorded at all?

Not everyone bothers to datadive for the story or raise npc affection to hear more indepth stories about the giants.

Or dig into the files to read NPC dialogues.

Dialogue is server-side, otherwise we'd have all the keyword responses already.

DAMMIT!!!

I wanna know, what's with the absurd amount of fortification around Shyllien, Hillwen, and that Mysterious Karu Forest Ruins.

Friendship....FRIENDSHIP :D....I don't really know to be honest...just wanted to always say that.