I have had it happen 3 times now where the boss will unexpectedly slap 5 times in a row, killing me. :/

Uninstall immediately

***** this boss and the entire shrina of amana

I dont have problems with the boss, i have problems on how to beat the damn area before it

the jester armour is useful for the fight but has low physical defence so i recommend not getting hit

I see a lot of comments about bosses where people warn that summoning is detrimental because an NPC isn't great and of course the boss' HP is boosted. For the most part I don't agree - having someone else for the boss to aggro on almost always outweighs the boosted HP. There are two bosses where I do agree that summons of NPCs are bad (not talking about human players). Old Iron King, where whatshername can get knocked into lava and is pretty useless, and here. The summon has a bad weapon for getting the Demon of Song, doesn't understand when it's vulnerable, and gets pretty wrecked by it. She'll do pretty negligible damage just because of the invulnerability mechanic, and for her weapon to work, she has to hang about right in front of the boss, where she gets smashed. Do not summon the NPC for this fight!!!

People usually say roll or dodge but you really don't need too ...well yes's for a boss like the old iron king you will do well to roll but for the other guys just use a damn shield . People need to use 100% protection shields more often because they stop almost all useless attacks from enemies.
That's how I bet the rotten , with a shield.
And plus's this boss is pretty easy because you can get a good few shots at it with your bow from the very start.

I took the NPC with me for the boss fight, however I couldn't survive till the fog gate. Later tried it myself and was able to defeat the boss solo in second try.

this boss is really easy for range attacking. Went in with a +7 Heavy crossbow and +8 alonne greatbow, didnt take forever either