Comments made to our Dark Souls Wiki
Seath is one of my favourite characters in the game. The endless research on magic, sinister experiments on humans and the fact that he has multiple agents roaming the lands like channellers and golems is so badass in a way. The prison section on my first playthrough was also the weirdest thing I had experienced in gaming. His boss fight is OK but everything about him prior to it gives me chills.
Fun fact: on your first encounter with Seath, you can turn around and press the conform button to leave through the white light. I believe you still need to die to him to progress though.
Confirmed. I went through fog wall, Boss-music activated, saw him, said "No thanks" and walked back thru fog gate. Next time, but not this time.
To be honest I don't see why some people whine about this boss fight. The boss is not hard. The boss is hard IF AND ONLY IF you are going for the Moonlight Greatsword. In other words, getting the Moonlight Greatsword is hard. That is the true boss fight: the struggle to catch Seath's elusive tail.

Otherwise, there are many ways to cheese him. Cheesing while circling, as the page recommends, works. You can also cheese from quite long range as he creeps at snails pace towards you, and then, when he finally gets there and starts attacking, bolt around him to the other end of the arena and cheese more. It's really easy. You can lock on from the other side of the arena and use any ranged attack you'd like. I figured it would be fun to use the Avelyn I just acquired in his Archives.

But getting the Moonlight Sword...good gosh that is hard. For one thing, you have to hit the last three yards of the tail (give or take). That little tail wiggles like crazy and sticks itself behind walls constantly. And if you manage to get behind Seath in a good position, he pretty much always will try to do his melee-slam attack, which you CANNOT block. Even if you block one, multiple other hits are on the way, and they will hit you even while you are on the ground (most attacks can't do that). Turtling is a non-option. Your only chance is to run far away from him. So maybe 1/4 of runs for the tail will result in a hit on it. And you really would not be wise to try to hit the tail multiple times unless you have a fast weapon. Greed is punished severely by his melee-slam.

TIP: do not let yourself get squeezed into a tight space between him and a wall. If he does the slam attack, and you can't get away, you're toast, even if you are level 80. When it comes time get behind him, circle around whichever side is farthest from a wall! This means if you might start circling, then fail, then you will need to turn around and run in the other direction, running right across him in front of his face!
Surprisingly, he will let you do this.
fellow dragon bros killlll the traitorrrrr gnaaaaaaaaaaaaaaa...
what a fkin joke of a fight this was
out of all 4 bossess that are required to be killed, Four Kings were the hardest

I used cheat engine to kill him on first encounter but no matter what I tried its muda you have to die! Death is inevitable :'(
Whats wrong with you people why only dislike?
Anyone else wonder how he reads all those books?
He has servants, who can bring those books to him.
The Dark Slayer sword will do the most damage to Seath.
Ugh trying to get the tail is cancer and the tail slams ,god damn