This will reward 22800 (22.8K) Souls on the first kill, and about 10000 (10K) on consecutive kills.
Since your constantly going to the bonfire to heal, there's no reason not to equip Symbol of Avarice to increase soul gain by 50%, along with Covetous Silver Serpent Ring + 1 (20%), Shield of Want (20%) and switching to Mendicant's Staff (20%) right after killing it. So he may be a little tougher, but you get more than double the souls. This is reset every time you go to the bonfire.
What it doesn't say is he has 150% extra health the first time you kill him and drops 8800 souls, there after he is worth 4000 souls. They recommend farming him via backstabs when he spawns, and waiting for him to spawn again.
According to the wiki he drops Drops 4000 Souls.
In Archdragon Peak theres a Man-Serpent Summoner who will endlessly summon Drakeblood Knights.
